Hi there.
It all really comes down to what u do with your system. If u use it for day-to-day tasks and u don't play latest games, u will be fine.
Sure, Vista it's still not so mature in general and there are some small glitches, but nothing terrible. I have done everything what i could think of to bring it down. Well I succeded once, but that was expected

There are ways of getting Vista (and every other OS for that matter) to its knees, but that's just fault of the end user
So, as i said, if u don't play latest and very demanding games, u'll be fine.
It's not a problem of these games, but again, drivers are not so mature too, especially x64 ones.
I also play latest games, not so much, but i have been lately 'cos of new HW. Latest nvidia 163.11 beta are performing perfectly in everything i play including: Stalker, Quake4, Prey, Doom3, FEAR, HL2 and others. I had problems with Stalker and latest official 162.22. That's it, I sometime play older ones too, these are also perfect. But i t doesn't mean that u can't have problems, i can't play everything out there

It will only get better. ATi drivers are a bit worse..
And if u set atomatic updates to just inform about them instead of downloading and installing them automaticaly, ur uptime can be enormous
