AFAIK the best quality compression right now is H.264, the newest MPEG-4 release, pretty much made for HD. Other will probably know more than me, but I've only seen it available in Nero Digital which might confine you to Windows only playback via the Nero player, or playback via the multiplatform VLC player, I'm not totally sure. There is also an Open Source version called X.264, I'm not sure how you use it, which program etc. You might want to check out Doom9.org for more info, plus other people on these boards might have some info. I do know it takes a long time to encode a movie this way, it took about 20 hours for my AMD Athlon64 3000+ to encode a full length movie using Nero Digital.