Daring Fireball has some information on a problem bothering a number of Mac OS X users, including me. From these links, you can see that there's a problem with font caches, which cause long (14 minute +) login times. Daring Fireball traced it to a bug in the Apple Type System, which uses Adobe type code to use cache.
In other words, if you've got long startup times, try killing the font caches.
Posted by Ted Stevko at March 27, 2005 11:30 PM