Yesterday Apple released iTunes 7.3.1 and Quicktime 7.2. With updated h.264 transcoding, numerous bug fixes and free fullscreen support for those without Quicktime Pro. It also provides iPhone exporting options and seems to enable 640×480 captures from certain iSights which were limited to 320×240.
Oh, and it breaks Rosetta.
Ok, not to be overly sensational, it does not break Rosetta for everyone, but a large number of users are reporting issues opening PowerPC applications on Intel Macs post Quicktime 7.2 update. It seems as though installing the OS X 10.4.10 Combo updater after installing Quicktime 7.2 has fixed the issue for some.
You might want to sit this one out for a while folks until the dust settles. You can read about this issue over at Mac Fixit: The QuickTime 7.2 disaster: Breaks all CFM apps on Intel-based Macs (Office, Photoshop CS2) for some; Problems playing Flash.