So far I'm liking 64 bit version of Vista. I had a little difficulty at first getting my raid driver setup, but I've managed to find drivers for the rest of my hardware. I'm still searching for what I think is the killer app, but overall I really like the look and feel of things. Of course I am a bit biased, but I went for nearly a year without using vista so I really didn't know what to expect in the final product. There are quite a few changes since the last time I ran it, and there's certainly a lot more polish. I think right now if I were to pick a killer application, it would probably have to be the speech recognition. Although speech recognition really isn't going to be used by too many people. I've been playing the speech recognition now for well over a decade, it is surprising how long it is taking to become usable. I will say right now that in windows Vista the speech recognition works amazingly well. I suppose it ought to given the powerful processors that we have today. The accuracy is amazingly better than the old dragon dictate system that I played with so many years ago. But only going to the tutorial, which does minimal training, I've been able to dictate this entire post.
(End of speech dictated text)
More on Vista's speech engine here.