Vista is a lot better in my opinion than what it was, more stable. I am not 100% sure of all your questions on 64 bit, as I'm using a 32 bit version. Your CPU, I think it's 64 bit, but I'm an AMD guy myself, however, most if not all chips from Intel/AMD are going to be 64 bit.
But Basic is supposed to be just that, basic, Microsoft has a new visual theme with Vista called Aero, it just makes everything not look so flat, let's you swap windows and different things, etc. Basic does not have that.
Home Premium does however, and includes I think some basic Windows games, and the Media Center software, etc. So builds off of Basic.
If you look at Vista Business, it's like a cross between the other 2, it's got Aero, no Media Center, no Windows games, but will run your pc games and what not, I know because that's the version I'm running. And I do all my gaming, etc on it. It may have a few more things for business users, but I'm using it on my home pc. As far as Ultimate, I've gotten to see it and play with it, and it's ok, very nice, it's basically got everything you could want or use. But honestly, for your money, if I were you, I would go with Home Premium. Why? Basic is ok, but a little more gets you all the little Aero features, Media Center, etc. But Ultimate is overkill if your just a home user. Also, Business is good, but you don't get the media center and what not. Why do I have Vista Business installed then? Money talks. Got it through my University(former university now that I've graduated) for about 22 bucks. 22 bucks looks a lot better than 110-150 or more.
Oh, nearly forgot, I did read that after Service Pack 1 for Vista comes out, that Microsoft is going to try and make it so you have to use all Verified Drivers, so if you have any modded drivers or anything you plan to use, forget it. Which definitely stinks. But that's what I was reading on another forum, so we'll see I guess.
Cheers ohiou_grad_06, I had a look at the link. I defo need Media Centre so that scratches Basic out. Ultimate seems overkill and I don't need its features re business and other stuff. So you're right, Premium seems the right one for me.
Or you could be like me and believe less is more, I just picked up basic for dirt cheap. In my less than common opinion I actually liked the fact some of the features were missing like Aero, Media Center, etc. Then again I'm cheap and a plain jane type of guy. If you want the fancies go grab premium, I believe the prices for retail dropped quite a bit too.