We got our hands on the Vista Service Pack 1 RTM bits today...  Took about 30 minutes to install from start to finish on my Dell OptiPlex 745 with 4GB of memory.  My cubicle-mate's PC took just over an hour on a Dell Dimension 9200 with 2GB.  So far I notice a definitely performance uptick, especially on boot and logon.  I'm also seeing better performance from small things like thumbnail views for minimized windows on the taskbar, pulling up the Start menu, and of course the obvious file copy speed increases.

All of this was present in the SP1 RC, but having removed the RC to get back to RTM in preparation for SP1 RTM, this is all a very welcome change.  Just proves once again that at Microsoft, Quality is SP1.