I don't know if this has been mentioned, and I found it by accident. In Firefox, you can drag a link (or highlight a URL in the address bar) and drag it to the 'Home' icon (just to the left of the address bar) to make that link your home page.
I don't use a home page (I have Firefox set to always open a blank page), but was kind of surprised when I saw this.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040602120804877