Of course they broke it!
Golly, I am some kind of futurist predictor guy. The new OS 10.4.3 patch does break Aqua emacs.
And here is yet another emacs build that works: EmacsInstaller.dmg
Update: this build, which works for me, complains about ncurses versions for other people. I suspect that it is the same old FINK pollution I have had in the past, but I built this version with all fink stuff turned off. So I'm not sure what is up. I'm working on it.
Update 2: OK, Apparently my G5 is corrupted beyond repair with some weird-assed ncurses library. I built a new EmacsInstallerFull.dmg that is nice and clean, and I had to do it on my mini. This version is a full /usr/local installation that will even work from a terminal, which is nice because it supports desktop save mode, unlike the version 21 emacs that ships with OS X. Enjoy!