Did you use non-SSL gmail over a suspect wifi connection?

My account got hacked a month ago. Loads of spam emails were sent out from my account, and I had a login from china in the access log.

My password was strong and unique to gmail. My list of most likely attack vectors they might have exploited to get me are:

* Non-SSL gmail over compromised wifi

* Logging in when travelling on a compromised PC

* There was a story that gmail had experienced a security breach and some passwords had been 'stolen' in early 2010. Not sure of the details.