Both SU and the stand-alone package hang for me (the stand-alone hangs during "Finishing Installation"), and coreservicesd sucks up my CPU time when I try to run QuickTime Updater or even open /System/Library/QuickTime in the Finder (which I did to verify that things were still installed correctly after the odd installation). Very odd, and probably just my machine. I've been putting off installing 10.3 forever, so maybe this will provide some incentive!
/me eyes his Panther disc wallet...
Edit: Yeah, I just wanted to vent since it wasted a bit of my time...for those of you who might suggest that I delete my system caches, you win. That fixed it. Hooray.