Ubuntu 10.04 RC x64 with all updates current as of 09:00PM PST.
My system is still up after the initial restart and I am currently using it.
Sound Preferences shows that I have no hardware listed and Output shows "Dummy Output"
Startup Applications that I disabled before the initial restart:
Evolution Alarm Notifier
GNOME Login Sound
Tested each application one by one. Everything is normal now with all of those disabled. Has since booted up fine.
One thing that was odd was X being in TTY1 and none of the other terminals were available. Just a blinking cursor.