Found this great utility through Scott Watermasysk's blog: Startup Delayer. I quote:
When Windows loads it's [sic] Startup file, it attempts to load every program in there at the same time. Therefore if you have quite a lot of programs starting when Windows starts, each program will try and grab CPU time so that it can load.
If each program tries to do this at the same time, you soon notice the slow down that occurs, due to your CPU trying to help all the programs to load, and your hard disk accessing multiple files.
Startup Delayer allows you to setup how many seconds after Windows has started, to load each program.
Works just as advertised. Just configure it to get those slow loading applications (Skype anyone?) to load up at a later time and save your quad-core from thrashing.
You can configure it to just work in the background, or with a visual GUI:
There's even an auto-config option to have everything in your startup menu startup at a set interval (say 10 seconds). Couldn't be easier or more effective so definitely worth the download (and works on XP and Vista).