Paul Thurrott has a very positive review of Vista SP1 here. Lloyd Ketchum has a bit of a rant about all of the Vista naysayers here. As I have said before, I have had pretty good experience with Vista. I installed SP1 on my teaching laptop, and I have noticed improved file copy performance, with no negative issues so far.
Especially if you have decent hardware, Vista performs very well. Good, new hardware has gotten so affordable, there is less of an excuse not to upgrade or buy a new machine.