Here's a pretty good article at CNet's News.com about 64 bit drivers. It's not just about Vista, either. The Mac OS X comes in for some comment, as well.
It's interesting to note that while they find some deficiencies in video drivers. those I know who are running 64 bit Vista at home or at work are really happy with the performance. The only qualification I have to make on this is that the peripherals and internal equipment they chose was guaranteed to be at least nominally compatible with Vista. Those who try running it without a bit of planning and thought are the ones doing a great majority of the complaining. That does not mean their complaints are without merit, just that they are somewhat out of proportion.
I have to admit I know nothing of 64 bit doings on the Mac. Linux, however, is quite another story.
I've had a little experience with Linux on the IA-64 platform. That's the Intel Itanium, for those of you who have not kept up with it. (Don't worry about that. Itanium is about as close to a niche platform as any of us are likely to encounter.)
I've got an AMD powered 64 bit Linux machine running here, now. I just wiped the 32 bit and put on 64 bit Ubuntu after a hard drive failure deprived me of my 15,000 rpm hard drive that was serving as a swap file. Basically, 64 bit Linux is indistinguishable from 32 bit, except that some apps have not been re-compiled for 64 bit, so the repository of applications is somewhat smaller.
Generally, I would say Linux is best situated in this regard, followed by OS X and then Vista. Still, Vista is not in such bad shape. Were I going to put up a Vista machine, I would be carefully choosing my components and I should think I could get along just fine once the machine is basically equipped. Software compatibilities are going away at a phenomonal rate and as far as I know, every application I would run is already well and truly ported to 64 bit versions of Vista.