I think a lot of the gaming problems are related to all the drm stuff in vista. Microsoft has really complicated vista with complex software and hardware requirements that all relate to drm and make the pc more expensive and less reliable.
More can found here:
http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html
Dont know if all of it is true as I am not tech savvy as most --- but it did raise my eyebrow
I think the problem with Vista is simply the lack of drivers. Also they trying to do a few things at ones and of course there are problems. They try to implement DX10, tight up the security of the OS, and let's not forget this is a brand new OS so of course there will be some software that will not work with Vista, so they need to be patched, or upgraded. Many people complaining and whining about Vista but they all seem to forget that when XP shipped 5 years ago it was not so hot OS either and everyone wanted to stay with 98. Even up to recently i remember everyone was complaining how crappy XP is with all the security issues with it, and now that Vista shipped the spotlight seem to moved on to Vista, and now all of the sudden XP became a good OS.
I upgraded to Vista and other than a few minor issues, but i am satisfied. If someone asks me why did i upgrade to Vista i usually say because i was so sick of looking at XP. I like the way Vista looks and feels as an OS. Sure it is not perfect but it is much better than the beta was. None of my games have any trouble running. (BF2142, BF2, GRAW, R6Vegas, Supreme Commander, Company of Heroes these are what i played recently)
As for Vista live it is an optional thing to get it. If you want to kick the crap out of console gamers online than you would have to pay for it, otherwise don't bother. So far what i have seen from Shadowrun which is the only game that will let you play against XBOX players, (for now) i will not pay for live. That game does not look interesting to me at all. It looks like UT from like 5 years ago, with different graphics. There will be much better games coming out for the PC where i will be spending my money probably. Crysis, UT3 and Allan Wake just list a few.
Sorry for the long post.