Did all 4 of mine last night (G4, G4, Intel and Intel) and all worked fine using Software Update… Though if I remember rightly, dont have anything plugged into the USB as the upgrade takes forever… Or maybe thats the MacMini just being its usual slow self! 
Mine also worked fine - G5 iMac. Plus I had several USB plugins. Go figure!
All right:-) Thanks for the feedback guys:-) I’ll upgrade tonight.
Software update seems to be hit or miss. Some people aren’t having problems, but a lot of others the install hangs. I let mine sit for almost three hours before doing a restart. Upon downloading the combo update, it only took about ten minutes to install. Whatever path you choose hitest, tell us how it goes. If software update works for you great, if it screws up then you know the other way to install it.
2 x iMac G5, G5 Powermac, 2 x Macbook white, and new Macbook, all worked fine with software update.
Makes me wonder why myself and others are having problems while others aren’t.
Friend of mine did his brand new Macbook Pro today, and guess what… same issues you were having, and its only 2 weeks old, yet mine worked fine! Very weird!
Yeah, very weird indeed. I’ve been reading stories on the Internetz about hanging installs.
I’ll update later tonight, see how it goes:-)
Aiiee!!! SMC update and 10.5.6 over 700MB…
I think I’ll wait and try it in the office tomorrow on the fiber connection!
The combo update contains both PPC and Intel versions. If you use software update from 10.5.5 it’s only 190mb or so. Still…
Update’s saying 377MB for the SMC and 355 for 10.5.6
Ajax approves of the Macbook.
Just got back from the office…late night. Ran the combo update. After the re-boot everything is fine. No glitches:)
My Mac inventory may not be as extensive but, 1 intel imac, one mac mini, and one new macbook pro, no problems with the update here
Carnevil gave us the heads-up on page 2 of this thread. 
No problems whatsoever…
Same here …