Dwarf Fortress.
Oh wait, that one was free? HELL YES! One of the most addictive games I've played in years. So good.
What's another one I've been playing alot of recently? Mount & Blade. So damn good and I only payed 15$ for it. Playing right now with a mod that adds gunpowder units as well as a whole slew of other tweaks to the base gameplay and it's like a whole new experience. Charging through rifle smoke to break the marching infantry lines is an experience you've gotta play yourself to know just how damn fun it is.
But you're probably thinking more recent games, because you strike me as the sort who thinks if it isn't a big-budget major release, it doesn't count for some reason. (Which is both stupid and naive I might add! You're missing a helluva lot of amazing games with that mindset.) So on that from I've been playing a fair bit of Dawn of War 2 lately and enjoying it. Love the more tactical approach the developers went with this time around and the races are as fun to play now as they ever were. Waaaagh! For the Craftworlds! For the Emperor! Snarlgnashfangdrip! The usual.
Empire: Total War is also incredible. Buggy on occasion, but incredible. Naval battles are absolutely sublime to watch, a joy just to see and experience, and there's so few games out that that pack such detail into even the most minute things so that it's a genuine joy just to *watch* the game be played. Gameplay is the same as ever, and although I know some people don't like it, personally I love the time period and think the tactics of the period are quite interesting.
Most recent game I bought? Freedom Force package on STEAM, think it was 6$, amazing value from what I hear and I'm looking forward to trying em out tomorrow.
Good times, good times! GREAT time to be a PC gamer.