I've read that Dead Space controls are awful on pc and you need to use a controller. You're better off getting that on a console if you have one. If you're looking for a cheap completely one dimensional game I'd suggest getting Condemned - Criminal Origins. It's a port of the 360 version, but I think it's worth playing and I got it for under $10 like a year and a half ago. You need to get Mass Effect though since it's a 3rd person shooter/rpg. That was one of my favorites that you can probably get real cheap now and the squeal will be out soon.
Good post. I plan on getting a 360 controller, since some of the others like Assassin's Creed will require it as well. My most recent console is a PS2, so it's gonna be all PC for me. As for Condemned, I downloaded that a few weeks ago and thought it was terrible. I've decided to add Mass Effect to my list. Also, I plan on pirating most of these, which will cut down on expenses significantly.