have played with Ubuntu 8.04 and have been pretty impressed so far.
That being said, I'm still happy between my XP desktop and OS X laptop (and Vista work laptop, but there's no choice in that so it's kind of moot...).
Wishing for either (both?) MS or Apple to do something stupid that will make me say, "fuck this proprietary OS shit!"
As it is though...doing fine in both regards on both platforms, and as such, despite all the goodness/progress made by Ubuntu (and other Linux desktop distros), I don't feel any real reason to switch over yet.
That being said, I'm still pretty sure that I'd never pay full retail for MS Vista. (although, if I could get it for free or next to free, yeah, I'd have to consider it....)
I'm flippant and indecisive.