If your pc runs Crysis, it'll run Far Cry 2 
My pc is over two years old, and 1 year old since I bought a video card, and it's seriously the best pc I've ever had... e6400, 4 gigs ddr 1000 ram (overclocked ddr800 to 1000), and a 8800gts640.
Runs crysis at 15-20 fps at ultra high, but I hate 15-20 fps so somethings are sacrificed.
Left 4 Dead is a no brainer... Been watching the game for months. Far Cry 2 is already preordered on steam. So is clear sky, i LOVED Stalker.
Also recently bought Flatout Ultimate Carnage, Race 07+GTR Evolution, Ghost Recon series, and Assassin's Creed. Mostly due to having my new 40" 1080p samsung lcd, and needing some games that use controllers.
Not gonna buy Spore unless Ea does a bioshock, but I gave it as an example anyway.
Too many good games lately, hopefully Stardock will spare those of us caught in the good games trap and give us time......