My favorite facebook Easter egg of all is changing the language setting to "Pirate." I apparently discovered it later than most, but it's revolutionized my bookfacing.
And MySpace and facebook are completely different. MySpace is the internet 15 years ago - embedded music, busy backgrounds, poor layouts, guestbooks, and probably blink and marquee tags. facebook is the internet today - everything is blue, information is pulled via seemingly sketchy means, it has some level of integration with seemingly every other major website, and you're spammed like crazy.
But facebook wins out of the two because I can play Bejeweled Blitz there. And because of Jim Halpert's line, "Yes, I'm the popular social networking site known as Bookface."