Anything with a valve labell on it (not a big fan of CS, but each to their own)
Billions of half life 2 mods, I'd recommend Dystopia and insurgancy
CoD series, except 3 and 5 (older is better other than 3, 3 was a joke)
Unreal series (didn't like UT3, but other than that I enjoyed them all)
Anything ID software. I liked doom3, but the real gems are the old games, wolf 3d, doom etc
Quake is generally well liked.
Farcry/farcry 2/ crysis. All good games, I'll group them together.
I liked MoH:airborne (that's the only medal of honour game I've liked since the ps1)
Stalker series is generally well liked, although it is a bit buggy
battlefeild series is well liked, although I don't enjoy playing it unmodded.
alien vs predator series
prey
bioshock/system shock. probably prefered the latter but bioshock is generally well liked as well.
That's all I can think of for now, that should keep you entertained for more than a while.
Billions of half life 2 mods, I'd recommend Dystopia and insurgancy
CoD series, except 3 and 5 (older is better other than 3, 3 was a joke)
Unreal series (didn't like UT3, but other than that I enjoyed them all)
Anything ID software. I liked doom3, but the real gems are the old games, wolf 3d, doom etc
Quake is generally well liked.
Farcry/farcry 2/ crysis. All good games, I'll group them together.
I liked MoH:airborne (that's the only medal of honour game I've liked since the ps1)
Stalker series is generally well liked, although it is a bit buggy
battlefeild series is well liked, although I don't enjoy playing it unmodded.
alien vs predator series
prey
bioshock/system shock. probably prefered the latter but bioshock is generally well liked as well.
That's all I can think of for now, that should keep you entertained for more than a while.