Don't ask what my new one means.
I just found it on some random website and liked it, so it has replaced Captian Falcom for the time being. EDIT: The previous was deemed too offensive, so I found a new one from Arkeis.
My current avatar I decided to reflect it upon one of my current favorite bands which is Megadeth. I love the album art for their album Rust in Peace as well as their mascot Vic Rattelhead. I went with the Vic Rattlehead on Rust in Peace.
I was in a mafia game in which I was the last member of my faction, the wolf was leading the village, there were four (yes, four) members of the other mafia left, and 6 or 7 villagers left. I changed my avatar to this when we were about final 5 or so, and I outlasted every other faction and the wolf, even though I didn't win.
I like it, and it stuck (although i wasn't such a 'die hard' in Diplomacy)