Personally, I'm not offended by the avatars with sexual content, but I do find them to be in poor taste. Very low class, and a reflection upon the individual using it. What does that tell you about that person?
There is a time and place for everything... Even on this forum. If you feel you must post images like this, please keep it in the Girls Girls Gilrs thread. That way, folks can opt to view it or not. If people want to see your girl's ass, they can see it there.
In addition, if one is so highly educated and accomplished, then act like it. The use of sexual content in your avatar and/or sig screams 'look at me... I need attention'. The whole 'me, me, me' aspect of it all just confirms it even more. Look what I can do. Look at how much I have spent. Look at MY educational background. Look at MY girlfriend Look at me, look at me, look at me.
Sad. Very sad.