I was perusing the feedback page at Yahoo (for their beta service) and noticed this link in the comments section, which I thought any interested in SSL might want to look at. I haven't read the article yet, but it seems Gmail rates somewhat high.
The most important piece being do not login to your accounts from untrusted computers. A lot of problems can be avoided if you keep your home computer up to date, use a wired connection to the internet, and stick to visiting web sites with good reputations. Avoid liking and clicking every facebook link that your friends send you is good too.