Rui CarmoWow. Besides 2006-003 (which fixes the image buffer overflow issues DB pointed out and quite a few more), there's Quicktime 7.1 and a Front Row update that mentions shared video libraries, something I've been meaning to play around with for a while.
Still no support for older Macs, though. Tsk tsk...
Hmmm... I must try setting up my home DAAP box to serve video. Where did I put those E3 press conference movies?
Ah, there's also mention of a Ruby fix in 2006-003. I haven't updated yet, but maybe, just maybe, they actually compiled it the right way this time?