I've got the 8500 All-In-Wonder + Windows XP Professional. My experience is not a good one!
I've had a problem wherein the machine is randomly rebooted during normal use. This has happened while using pcAnywhere, while using Internet Explorer, and a couple other basic scenarios. No games or other taxing apps required.
It's a pretty nasty problem because it causes a blue-screen/reboot. After rebooting, Windows reports that it has recovered from a serious error (no kidding) and that the 8500 seems to be the culprit.
Yes, I am using the latest driver.
Anyway... I'd be interested to hear if anyone else has experienced this level of difficulties.