"What's really frustrating is that they can, apparently, buy and use your own e-dress" I've had spam that said it was from me, and also bounce messages saying "my" sent spam hadn't been delivered to some random person I don't know.
Unfortunately it's trivially easy to put any email address in the "From:" header of an email and it always has been. You don't have to buy anything or hack anything to do that. I could send anyone an email that said it came from president@whitehouse.gov right now.
As for Facebook, I'm glad I've avoided it and will continue to do so. MySpace is not quite so bad; I did get phished once but it was quickly detected and sorted.
There's no point in trying to hide your email address. If anybody on the internet has it in their address book (e.g. your friends, relations or business contacts) it isn't safe; just one of them needs to get a malware infection and your email address is all over the spam market.