Well this is my list
1.Max Payne
2.Max Payne 2 The Fall of Max Payne
3.Mass Effect and Mass Effect 2
4.F.E.A.R. Series
5.BioShock and BioShock 2
6.Fallout 3(buy the game of the year edition it has all DLC's) and Fallout New Vegas
7.Dead Space and Dead Space 2
8.Company of Heroes series
9.StarCraft(Brood War expansion pack) and StarCraft II
10.Half Life series
All are good games, they never get boring, there are, a lot more both I don't think that you are ready to give all your money just for video games.
Add Dawn of War II & Chaos Rising, Battlefield Bad Company and Darksiders: Wrath of War to that list and I think that might be an excellent list.
[Edited by AdmiralAckbar, 1/24/2011 9:11:56 AM]