Vista is one bloated goat...it takes forever for just about anything. Throw RAM at it and the latest greatest hardware...you will be rewarded. Seems to really want a full GB of memory to really get the high performance experience...XP w/SP2 wanted 512MB RAM over 256MB (more like 384MB 256+128 at least) RAM that SP1 worked (not very well) with. Seems like every major revision means doubling the RAM.
From using the 'Dell Express Upgrade' from XP to Vista, it took me about an hour once I had all my files backed up. To log on and get all users set up, it took another half hour.