I started the 73.6 MB Win 7 SP1 update at 3:16 am west coast time through Windows Update and it downloaded in about 5 minutes, then the installation took another 5 minutes and restarting the computer plus configuring the Service Pack took the final 5 minutes and my desktop was back up and running 15 minutes later at 3:31 am.
There was about 13-14% CPU usage for a few minutes but at 3:36 am mscorsvw.exe phoned Redmond and CPU usage dropped back to 0% as it normally is.
I have yet to notice any irregularities as a result of installing Win 7 SP1, but I will post any problems should they arise.
The SP1 installation left 1 restore point and an additional 1.6 GB more data on the C partition than the 19 GB that were present just prior to SP1 with 920 MB of the increased amount being Service Pack backup files which can eventually be deleted. I have also included a screen capture of the extent of the highest amount of defragmentation within certain files on the C partition after the successful installation of Win 7 SP1.