What PC specs do you have and what graphics settings are you running the game at?

Bioshock runs on pixel shader model 3.0 (or higher), having a card that runs on 2.0 means the game will be rather sucky. I've heard there is an unofficial patch so it will run better not not tried that personally.

Warhammer: Dawn of War Anthology is only £18 now-a-days and is a superb game with two good add-ons. Probably the best value for money you'd get right now.

Football Manager 2008 and The Witcher

although I have Company of Heroes and Psychonauts arriving to tie me over until then :)