With SP1 out for Vista, I finally decided to give it a try. All in all, it's not as bad as I've thought. If anything, it's more annoying than frustrating, especially if you're used to doing a lot of system tuning as certain things like control panel options, which have been steady since Win2k, have been moved around and slotted in other places. After a lot of poking around, looking up where thing have moved to, etc., it became much easier to work with.
UAC's are the single most annoying thing on the planet. Turned them off immediately to stop the nagging.
I can see where MS was meaning to go with Vista and I'm hoping that they'll keep the good from it and finally make the full jump with whatever Windows 7 ends up being. They need to just tell people that things are going to change, deal with it and prepare for it, like Apple did with OS X. If the rumours of using VM's for backwards compatibility in Windows 7 are true, then it looks like they're headed in that direction.
The one big difference I noticed was that, holy sh*t, is this thing a pig in terms of footprint!! I'm working with Vista Enterprise and I'm up to a 46GB install footprint. Office 2007 must have some big ass files in it to have added over a full GB of footprint over office 2003. I have yet to install either Nero, Roxio Easy CD Creator, Visual Studio 2008, the MSDN library for VS2008 or Adobe CS3. I'll be interested to see exactly what I'm up to in terms of size of the installation when all is said and done.
Thankfully there have been no compatibility issues so far. We'll see if that continues. As I'm not a gamer, I think I'll run into far fewer issues in that regard than others or at least hope that's the case.