I use gmail, granted the penalty is Google data-mines it so I don't send anything too personal, but the spam filters in are exceedingly good.
Yahoo on the other hand... let's just say the span I got was not family appropriate. Somehow my email wound up on every bad site you could imagine. I quit it and let it fill on up. Hopefully Yahoo has devoted an entire server farm to deal with my dead account. I think it was a result of having a pissing-match on a tech forum years ago, my opponent thought is would be fun to submit my Email everywhere.
