As with any Microsoft product, you'll find opinions very split on this issue. I like Vista a lot more than XP, and it's because of the little things. For instance, I find Aero quite pleasing in that it smoothes a lot of effects, but doesn't interfere (as some of the Linux alternatives do). UAC hasn't been a problem for me - it only seems to come up when I update software, change system settings, or run Visual Studio (and the latter only when I want to use IIS, which requires admin privileges to debug). The new start menu does take some getting used to, and I sort of prefer the expanding one they had in previous versions, but the search is a nice addition; either way, it's not bad, it's just different.
On the other hand, I would strongly suggest that you have at least 2GB of memory. I two computers running Vista, one has 2GB, the other has 4GB. They both run fine (the 2GB is a little slow under a heavy load), but having less than that would probably be frustrating.
Don't forget the insignificant cost... and it might be worth considering taht SP1 is just around the corner - supposedly..!
I have it on good authority that SP1 is, in fact, "just around the corner"