Earlier today, I mentioned that it wouldn't be out of the question to write a Firefox extension that would grab profile data about your Facebook friends as you view their profiles so that you could take that data to another service.
Given that, allow me to introduce Facebook Scavenger. It's a Firefox extension that saves data (including e-mail addresses) from Facebook profiles that you view and then allows you to export that data in CSV format.
Note that this extension does not violate Facebook's TOS since it does not automatically load pages to retrieve profile data; rather, it reformats data that you have already seen on pages that you yourself loaded. Robert Scoble could have saved himself a lot of trouble (and avoided a lot of that nasty publicity that I'm sure he hates ;-) had he just used this extension for a few days.