Well, a lot of that probably has to do with personal taste.  Do you like them big and round and soft, small and tight like grapefruits, somewhere in between, with thong tan line or without?  So many choices.  There's four SD area girls that were entered in last years Best Buns contest (see link below).

Hey wait a minute, isn't it time to have another contest?  Time to interview all the applicants!

I'm sure you will get much debate on this subject. It's all a matter of taste. My favorite as of recent, is probably Jenna Banks. Very petite body with a nice bum. Pictures do not do it justice.

Also saw one of the Canadian girls Sophia visiting LA (sorry not SD). I been looking at her behind for a long time.