Pure PC Games

[Blue Musician]

They should also be fairly recent.

Mmmmmm, Sorry to say this, but I cannot recommend most recent PC games, since most of them aren't that good. But I will recommend you many games, and if you do not play them, you are going to lose a great time with them:
Every SH game, STALKER, Crysis, FEAR, Far Cry (by CryTek), Beyond Good and Evil, Freedom Fighters, System Shock 2 (you will have problems running it though), Thief Trilogy, Braid, Call of Cthulhu Dark Corners of the Earth, Grim Fandango, Psychonauts, GTA Vice City, Max Payne, Penumbra, World of Goo, The Path, The Void, SC Chaos Theory, The Misadventures of PB Winterbottom, Mafia, Dead Space and Metal Gear Solid 1&2.

Why do you only want recent games anyways? Graphics aren't everything, and most games have shallow gameplay now days. I recommend you to not care at all about recent games. Old games will always be the best ones EVER!

 

[Jaranja]

Absolutely, have fun.

Supreme Commander 2 is a good huge-scale RTS. Warhammer: Dawn of War 2 is a good RTT.

Tell you what, go on steam and look up "THQ Complete Pack", buy it.

Supreme Commander 2 is terrible compared to the first game. I can't think of a better way to describe it than the noobiest RTS I've ever seen. Don't get it. Also, Dawn of War 2 is great. So is Dawn of War 1, which I like even more.

Well, I can agree in some respects. Artillery for example.

Dawn of War 2 and Dawn of War 1 can't be compared because they're completely different

 

[Zaik]

If you liked Diablo 2, Torchlight is a great alternative until Diablo 3 comes out.
Three classes, Warrior guy, Mage guy, and girl with a gun...And a doggy!!
It should be only $10 on steam right now, if not, $20

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Torchlight regularly goes on sale for $5, i'd recommend waiting for that before purchasing.