It had been a few days since these updates were announced and I saw no problems at MacInTouch or other Mac news sites that led me to hold off any longer, so I repaired permissions and backed up my personal data and applied the updates. Twenty minutes and a reboot later, and all’s well; everything runs fine, the apps installed perfectly (I did another permissions repair after the updates too) and iPhoto in particular seems a bit snappier than it had been with my 4500-photo library.
I haven’t noticed any differences with iTunes yet, and I don’t use iDVD or iMovie much. I’ve played with iWeb a few times to see how it works but since I already maintain this site, I haven’t had much use for another site on an Apple-hosted server.
Another series of software updates I can add to the list of upgrades that caused me no problems, though as usual I’d never make such updates without backing up first.