Mac OS 10.5.6 problem - the quick summary

The 10.5.6 installer was screwed up. It may be fixed now, but most geeks will download the entire 700MB+ Compo Update.

There are other things broken however ...

Mac OS 10.5.6 problems? Apple suggests shampoo | Register Hardware

.... It should also be mentioned that Apple's 'advice' doesn't address any of the other problems experienced by 10.5.6 updaters, such as dropped network connections, audio 'pops' upon restart, Mail.app refusing to quit or failing to connect, problems with Apache and Contribute, and iSights going blind. (Oh, and if this last one has happened to you, make sure to reset both the SMU and the SMC.)...

I'll wait another week.