Of course, this is why there is the Games for Windows initative. It's an
attempt by microsoft to makes gaming on PCs as easy as possible. With every
major OS release there is bug and problems with the older stuff (and not so
older stuff) Once the game developers start working with Vista more, things
will smooth out. Remember, Vista is technically only 3 1/2 months old from a
retail perspective. Still very young and new.
I suggest waiting as long as possible to upgrade to Vista. If XP is working
well for you, There just isn't any real advantages to justify Vista at this
time.6-9 months, there will be a little more when the DX10 games start
coming out, but even then it's only a few games.
You can check
www.Vistareadygames.com to see what if your game is listed has
being tested so far and whether people got it to work.