I recently bought ATV Flash and installed it.
Only Boxee and XBMC work OK. The problem is that I select the video .AVI I want to play and the finder crashes. I tested it with two different AVIs, in a remote SMB HD and copying the file to the ATV with FTP. Same result. Nito TV, Shappire and File crashes the finder (maybe same media player ?).
Other media type videos work fine: DVDs, MPGs, MP4s and they play fine.
Boxee and XBMC don´t show the same behaviour. They play AVIs seamlessly.