Vista isnt full of bugs, its the fact that alot of software isnt compatible with it. Actually I shouldnt say alot but things like SolidWorks 2006, Nero, etc... Dont work. Its not as much as you think and most of them patch with Windows Update. So your answer is no, it doesnt have alot of bugs. To tell you the truth, I've had less problems with it then I have with XP. Thats just me defending it though, I find it faster and more efficient. Also its more clear.
As to answer your question about games, Direct X10 is coming out sometime by the end of the year. This is going to be a major increase in performance and productivity for games. I wouldnt doubt that a new Graphics Card should be upgraded, but it should bring amazing performance for your graphics card. Games will eventually require Vista... But look at it now, some games still only require Windows 2000 and few need at least XP. I dont see much changing (Except halo 2 for pc, thats vista only).
Jack Musick