Video playback was excellent, and our test HD WMV file ran flawlessly--something no other Netbook has been able to do. Web-based video is a bit of a different story, but an updated version of Flash (reportedly available in November) will let streaming Web video take advantage of the GPU. For right now, Hulu on-demand content ran decently as-is, but not radically better than other Netbooks.
So, we're pleased to see the Flash player 10.1 update is available (as a prerelease version) for download. It's not even in official beta form yet, but we downloaded and installed it on an HP Mini 311 Netbook to test it out.
Even in this early form, full-screen HD video via Hulu was much improved. Playback was mostly smooth, with a tiny bit of occasional stuttering. Prior to the Flash update, low-res Hulu programming played reasonably well (and even then, not in full-screen mode), and HD video was very hard to watch.
If you're interested in installing the pre-beta version of Flash 10.1 on your Nvidia Ion Netbook or Nettop, you can find it here.