I'm not a 'gamer', but I do like playing games. Doom3 engine based games (Doom 3 and Doom 3 ROE, Quake 4 and Prey) are not playable. While they install and technically run under Vista (both 32 and 64 - swapping back and forth is pretty easy with Winclone), they perform horribly. No driver conflicts here, it's mouse lag and screen synch issues combined with complete 60-90 second freezes while the hard disk grinds away when you save something. I've installed updates to both the games and the OS, I've tried different video drivers, I've tried running games from different drives, etc. Nothing makes them playable.
They run perfectly under XP.
On second thought, maybe I am a hardcore gamer
Valve's various games (Halflife2 and Portal and such) all work great under Vista, but I have a mod I've been trying to work on and none of the editing Source SDK tools work (random Exception errors - I'm on the Steam forums also, lots of Vista only issues).
Again, work fine under XP.
Adobe Creative Suite (original) wouldn't activate after installing, then after bruteforcing it over the phone (it wasn't a registered too may times problem), most of the programs won't run - just results in a 'Program .. has stopped responding' dialog.
Visual Studio [Express] is a complete pain in the ass. This could be a straight up x64 issue though.
On top of all of this, significant performance decreases (games, disk IO, interface response). Vista is far from snappy.
I could go on, but rather than complain, I just wiped my Vista64 partition. I have a Winclone saved of my fresh Vista32 partition, and also my XP setup. Going to wait a little bit before I decide what to restore.
If all you do is email, web, chat, maybe a game, Vista is probably fine. But if you actually 'use' your computer (or make money from it somehow), it doesn't seem to cut it.