We're talking about the asus eee PC 900 (Celeron @900MHz, 1GB ram, 16GB ssd).
All working fine:
GPU: ok
Sound: ok
ethernet (atheros): ok
wlan (atheros): ok (ath5k is preloaded since ubuntu 9.04)
Haven't tested suspend/resume. Tbh, I haven't used that feature in my life on any pc/notebook :P
In ubuntu 9.04, the fn keys for the wifi don't work (you can always disable the wifi from bios).
In ubuntu 9.10 all the fn keys work.
EDIT (29/01/2010): The netbook also works with the current debian testing release (current=25/01/2010), out of the box. The only thing not working is "mouse clicking" with touchpad, but it's probably some setting I didn't notice.