I am actually incensed. I updated two of my machines, and BOTH failed being stuck in a loop on boot.
Very very poor indeed!
I don't know what made Apple post this update that caused true and deep problems with absolutely EVERYthing or anything!
After a painful two days (and NO backup!!! tested on two machines), I have managed to re-install OSX 10.6.7:
1) boot from OSX Snow Leopard disc (the one from the Box set)./ Macbook Pro Install disc 10.6.3
2) install OS 10.6.x with "customize" selected to run ONLY the greyed out minimum requirements onto the faulty 10.6.8 disk.
4) voila: the old (10.6.x) user account was back with ALL files and folders and applications (including mail etc, so all preferences were intact!)
5) run disk permissions repair
6) run software update EXCEPT 10.6.8
7) install 10.6.7 combo (standalone)
8) repair disk permissions
9) run software update (it will bring up Java update)
system restored - above steps correct as at 28th June 2011.