You email password is stolen by
-hidden trojan/keylogger on your system
-phishing site
-MITM attack via wireless or Tor exit nodes
-SSL counterfeit signatures which are in the wild everywhere now thanks to Comodo
Watch this if you think SSL is safe
http://www.youtube.com/watch?v=Z7Wl2FW2TcA
Paranoia aside use a high entropy password and don't type it in on a questionable machine that could be backdoored/zombied/trojaned whatever. A liveCD helps if your email is really important and you're moving lot's of huge paypal money or something