Jacob -- remember, this is the guy who has a terrafarm behind the router.
Crappy -- I know you're smart enough to know this, but just to be sure -- just because emails were sent from your accounts, doesn't mean that your accounts were actually compromised. In fact, a lot of times, someone who has you in their contacts is the one compromised, not you.
What other evidence do you have that your emails -- or even your computers -- were the ones actually compromised? If you're sure, my primary response would be the guessing of passwords as has already been suggested.