We upgraded from Vista to W7 Home premium 64 bit, and yes, it was as simple as putting the upgrade disk in the drawer and an hour and a half later W7 had magically appeared in place of Vista. We have had no problems with drivers/favourites etc etc, but I guess it depends on your set-up.
The upgrade disk was supplied in the post by Mesh, who we bought the original machine from just a coupple of months before W7 was released.
W7 seems pretty good.