note: This article is intended for a technical audience -- and while it seems to works for the two systems i've tried it on since, you should use caution when modifying a production system -- caveat emptor.
Not-so-simple one line fix that shaves a good 5-10 seconds off the boot up time of a 1.8ghz HP Notebook machine.
Open a terminal and use sudo with your favourite text editor to edit the /etc/init.d/rc file, eg.
sudo vim /etc/init.d/rc
Then, around line 24, change:
Save the file, then the next time you reboot -- Ubuntu's base bootup speed will be even more similar to a Microsoft operating environment than ever before.