Oh yea this SP 1 takes forever to install...
I recommend a couple of things for easing the Vista SP1 pain.
First run the SP from the command line and use these switches.
/unattend /forcerestart
After the monster has done it's thing run this command to clean out the uninstall cache files.
vsp1cln /quiet
After all that a good disk defrag and running shrink is also advised..
Blake