Best, Most modded PC games of the last several years

[Imperioratorex Caprae]

I went crazy once while modding Skyrim. I just started throwing random mods together and seeing what happened. I got to Whiterun to witness the battle of 1000 armies... Macho Dragon Randy Savage summoned an army of werewolves to wreak havoc upon the hapless forces of the bear clan while something happened with the weather and lightning started randomly striking, Dracula appeared as well as some crazy ass giant stone creatures appeared before the entire game crashed. I wish I could have got a screen shot of all that but I was too in awe and fits of laughter to be competent enough to press the button... "OH YEA!"

 

[Xeros]

Quoted for relevance.

COMPLETE makes STALKER easy. Use Reclamation. Zone Reclamation for SoC (bug and optimization fixes), Sky Reclamation (bug and optimization fixes) and Pripyat Reclamation (bug and optimization fixes).

No fancy graphics (though Clear Sky on DX 10.1 is STILL beating many AAA games... and I am not kidding) mods. Though you can mount them optionally. This is the way to play STALKER for the first time.

True, Complete drops the difficulty considerably. In my opinion it becomes a more fair, user-friendly experience, as well as gorgeous, but to each their own. The "gorgeous" part also means you'll need a semi-hefty rig to keep it running smoothly. Zone Reclamation is also excellent, as is L.U.R.K. if you're into making spooky games 2spooky. As for a first playthrough, however, I'd recommend doing it vanilla so you'll know exactly how you want to tweak everything.

 

[Joccaren]

Anything Blizzard.

Warcraft 3... The number of mods... Well, maps, but they were essentially entirely new games half the time. Evolve came out and I looked at it like "Why would I buy that? I've been playing it for years for free, but better". The number of different types of games is astounding. Sadly, as always, you need to dig through a lot of shit to get there.
Starcraft 2 is also ok on the modding scene. They made the modding engine more powerful... But they kinda fucked up in that they made it a bit too obtuse to use. Still some amazing maps that get made though.

Naturally Skyrim is highly moddable. Never got to the point of actually playing it properly in the end, too busy getting, editing and running mods to try and fix that broken-ass game. Took too long and I lost interest, but at some point I might return, fully mod it, and then start playing again.

The Civilization games also come with a surprising array of mods. Fall From Heaven II for Civ IV was amazing, and I pray that one day something like it will come out for V. Beyond that, the number of slight gameplay alterations, re-balancings, new civilizations, different resources, maps, altered unit graphics... A lot of cool stuff, even if the base game does end up remaining essentially the same.

Sins of a Solar Empire also has a lot of mods. Personally I just use my own, and rebalance the gameplay to more my flavour.

And lets not forget Kerbal Space Program.
Or Minecraft.

There are way too many moddable games these days. I spend more time modding games these days than playing them. No complaints.

 

[Zykon TheLich_v1legacy]

Dawn of War is an even better game with mods. There is one that adds in a whole Tyranid playable race, and my personal favourite, Annihilation for Dark Crusade, that just adds on to what is already there, and makes the game a lot more fun to play.

One of my answers and quoting you just to make sure the joy is spread to all: You've played Ultimate Apocalypse: THB yes? (moddb)

Also the standard FO3/NV and Oblivion/Skyrim. (nexusmods)

Finally the Caveman to Cosmos mod for Civ IV, from the Civ fanatics forum. Unfortunately I can only get so far before it exceeds my RAM limits and shuts down. It's a mod, so it's not particularly efficiently written, but for a game from 2005 to exceed 8GB of RAM is pretty impressive.

 

[CeeBod]

I love mods but I really hate getting them to work - I definitely wouldn't ever have the patience to be a game tester!

A couple of months ago I spent 3 full days getting Skyrim modded to the max (183 different mods running at once according to Mod Organiser!), cleaning mods with TESEdit, creating Wrye Bashed patches, checking for orphan scripts, making sure there were no conflicts for the levelled lists, the whole 9 yards. It played and looked absolutely awesome for about a week, then started crashing hard. After the initial 3 full days of getting it to work in the first place I just want to play it not spend my time bugfixing, so I haven't played since (

 

[Wary Wolf]

A bit old now, but I remember having a lot of fun with some Freelancer mods. Another example of mediocre game made kick ass by the modders. Some of the better ones made the game wicked hard and made it feel like you truly earned that big mo' fo' star fighter.

Going back further I remember enjoying some of the mods for the old school RPGs like Baldur's Gate and Might and Magic.

As for Skyrim I haven't gotten very far with it ever since I've been playing dead-is-dead on Legendary. Still, I got through most of the main side-quest-lines, so something that made them a little trickier would be good.

 

[LaughingAtlas]

I've gotten a lot of fun just in modding Left 4 Dead 2. Really, just starting up the game to see I'm toting a shiny, golden gun alongside Jack Skellington, Harley Quinn, and Princess Celestia while I play Bill cosplaying as Ebeneezer Scrooge (a thing that really exists), with the bullets all replaced with lasers and laser noises, (and SO MUCH crap I've exchanged the melee weapons with) to go cutting through hordes of orcs and half the special infected wearing bright, neon clothes (helps see them coming, tactical silliness!) is enjoyable all by itself.

 

[vallorn]

TF2... I still come across weird modded servers and custom maps now while playing the game.

And TF10X10 on Koth_wubwubwub is always good for just sheer mayhem.

And I guess the Bethesda engine games. But a lot of those mods are kind of necessary fixes more than upgrades. (like fixing Skyrim's leveling system and balance to act like it was made by competent people.)

 

[baddude1337]

Modded games, total conversions, or full standalone games seem to be some of the only things I play these days.

Most recently, I decided to get a joystick and gave Diaspora a spin. It's a standalone game on the Freespace engine set in the re-imagined Battlestar Galactica series. Honestly, it's amazing how much it feels like the series. Captures the space battles and what I wanted from a BSG game perfectly.

On a similar flight sim note, is X-Wing Alliance. The game itself has some fantastic HD model and backdrop mods which make the game look considerably more modern, but there are also straight up remakes of both X-Wing and Tie-Fighter for it, making it 3 massive games in one.

You did mention Half Life 2, but Half Life 1 and GoldSRC in general has a decent modding communitty. There is a pretty impressive HD content pack for Half Life 1, it's expansions and many of the popular campaign mods like Azure Sheep called the Trusty packs. Then there's also Cry of Fear, a standalone survival horror game that is completely free and is one of the better survival horror (and Silent Hill, which it is heavily inspired by) games to come out in recent memory.

Bethesda games are always have very active modding communities. Hell, Skyrim was only really playable for me after installing hundreds of mods. Hell, modding these is practically required with all the community patches and fixes you need.

Battlefield 2 has extensive modding and mod support too. Notably Project Reality and Forgotten Hope 2, which are the only 2 military shooters you need, complete with 100+ matches and bot support for most maps.

Dawn of War, already mentioned. Although most of it's mods these days are basically compilations of parts of older mods, it's still going decently strong, and practically every race and thousands of maps are now available for it.

The Total War series, particular Rome and Medieval 2, are still extensively modded to this day. My favourites are Roma Surrectum for Rome (IMHO the best mod for that game), and Third age with (a customised) MOS submod, being the best Lord of the Rings experience out there.

By far though, the most active modding community I have seen is the one that started it all - Doom. Doom has active mod development on multiple sites to this day, and over the decades countless gameplay and map mods have been created. Here's just a slice of some of the greats:

 

[Angelous Wang]

Statistically speaking modded Skyrim obliterates all other games.

http://www.nexusmods.com/games/?

Just look at those download numbers.

775 million.

Personally I've played and modded:
Skyrim
Fallout NV
Dragon Age & Inquisition
Dark Souls
The Witcher & 2 & 3
Dark Souls
XCOM EU
Vampire TMB
GTA V
TW Shogun 2
Civ 4/5/BE
Sins of SE & Rebellion
SW KOTOR & 2
Star Trek Legacy.
StarDrive
Endless Space
Galactic Civ 3
Fable TLC
Evil Genius
Far Cry 3 & 4
Sims 2 & 3

 

[thebobmaster_v1legacy]

Only games I've played modded are KOTOR 1 and 2, and Dragon Age: Origins. Of the 3, I'd say I liked the finished product of DA:O with mods best, but the mods I added for KOTOR 2 had the biggest impact, if that makes sense.

 

[JohnnyDelRay]

I just mod what takes my fancy nowadays, though when I was younger I would spend hours browsing and updating games like GTA: San Andreas. Some of the additional fan made maps and stunt parks were great. Loved to get into the handling files and tweak the cars to be stupidly fast and handle on rails, or be awesome airport drifters. Also modded a lot of Doom and Quake, and Counter-Strike beyond recognition.

Now it's more out of practicality, or to change a little function here and there, give me more carry weight or something stupid like that. Although to a much less degree, games I have modded in recent years include:
-Resident Evil(s) inc. Revelations
-XCOM
-Max Payne(s)
-Minecraft
-Assetto Corsa - my main modding game at the moment, huge community out there that just loves it's sim-grade handling and the cars and tracks are great, even if they are converted from other games.

Haven't modded anything by Valve in the longest time though, too scared of getting VAC banned for something dumb like that.

 

[KingsGambit_v1legacy]

I've had a blast with many modded titles. Of the ones which include a toolset, Skyrim is the most obvious for just how large a community sprang up around it. Once all the sexy armour and sexy companion mods are sifted out, there's some wonderful stuff for adding many new items, gameplay tweaks and visual improvements to name but a few.

I also prefer my ME2 and ME3 modded coalesced.bin files. I made many tweaks that eliminated a lot of the boring stuff from those games, not the least of which were the minigames. Tweaked weapons and outfits also means I can enjoy the sights and sounds of favourite gear and just have fun with the gameplay and story without parts I'm less interested in.

I found a nice mod for FC3 that makes some nice tweaks too, but the game is very mod unfriendly. Without proper tools, it only supports a single mod at a time, thus it's an all or nothing approach where short of making my own, I have to take all the changes whether I wish to or not.

Some older games that are great modded are Vampire Bloodlines (community patch) and KotOR2 (RCM), both fan made that include numerous fixes, restoring cut content and tweaks the vastly improve the story, conversations and experience overall.

I'm sad more games don't include toolsets any more. I still love seeing new ideas, content and so on come out from fans which gives a game replayability and invests me more in the experience. But replayability is anathema to modern AAA game design where publishers would prefer games to expire after a year and gamers buy it again with a higher number on the cover.