On XP I used a program called Startup Delayer. This allowed me to let my AV and firewall load 1st, then spread out the rest of my startup apps to allow them to open before the next started. Worked quite well. Right now on the site it says he is completely rewriting for Windows 7, so that isn't for you just yet, but keep an eye on it: Startup Delayer
A few days ago I posted in the reboot speed thread a new program that I did try, but deleted after because I didn't need it, but it should allow you to delay the program, not sure by how much though: Saluto
Watch the video. It's new so doesn't yet have recommendations on some major software, so we'll have to see how it develops.