Vista rots. Some problems I've encountered so far:
Foobar stops playing music after the screen saver goes up. It's oh so fun to try to listen to music while constantly toying with the mouse to make sure the music doesn't stop. I imagine there is an intuitive solution somewhere in the universe, but I doubt it can be found within Vista's settings.
Creative just released beta drivers for the EMU line. So far so good actually, but prior to that I had numerous problems running Media Player Classic... often a DVD would start up and I'd get crackling sounds. If I stopped or paused a movie partway through and then restarted I would also, without fail, get this crackling sound. I think the beta drivers solved this.
Many programs released as "Vista-compatible" are, in fact, not.
My DSL provider still hasn't released anything close to Vista-compatible software. Not a huge problem, I can set that stuff up manually. Unfortunately unless I'm running some kind of software that downloads something, and often times even if I am, my connection will fail when I go to work. Kinda defeats the purpose of having a perpetual connection that should be bringing in the goodies while I'm not home. The fun part: to get the connection going I must disable the connection and renable it manually. Every single day.
Vista is not intuitive. XP isn't exactly intuitive either, but with Vista all those settings you can access are not only randomly sprinkled all throughout the system, they are also buried under a "user-friendly" layer that's supposed to make it easier for idiots. All it really does is put settings and functionality a couple steps further away.
The view setting in all my folders changes randomly. Just about every time I open any folder. I actually started a thread about this. This handy feature has been a Windowism going back to 98 at least, but with Vista it's like Windows just took a potent dose of death crack.
Anytime I do anything my fan bumps up to high speed. It's like the tiniest little operation sets Vista off into a cascade of attempting to calculate a Mars landing for NASA. I hope they land safely.
That security feature that asks you to confirm every last execution is insane. Whoever thought of that one was probably in the middle of a divorce and dipping heavy into the booze. Yes, you can turn it off, but you get to see a security warning each and every time Vista loads if you do.
Any time you end-task an unresponsive program Vista takes it very personally. "Is everything okay? Did something go wrong? Do you want to tell us about it? Go ahead and cry, it's okay."
IE7 runs really slowly in Vista. I'm pretty sure only grandmas and office slaves are using it these days, so no biggie there.
If I'm using the computer when AVG goes to make an update Vista gets very discombobulated. For some reason AVG's update process then works in some mysterious background land and I need to visit this land to confirm operations that never actually execute even when I do. Fortunately I'm not usually using the computer when it updates.
Otherwise Vista is pretty darn good. I turned off most of the bells and whistles because, ya know, who cares?