I also think price is a number one factor for most people when buying a first snake. I certaintly wouldn't have purchased a ETB or GTP as a first
Looks are good too but then again some of the most beautiful snakes in the world aren't great to begin with.
Temperment is very important, this is another reason why I like Ball Pythons as a first choice. A baby corn, its bite might not hurt, but they bite. Most do anyways. They flip and flap all over the place. *Most* BP's are relauctant to bite, and generally stick around during handling and this can be good for a beginner IMHO.
Size I think is super important but look at all the fools who bought a burmese as a first snake only to realize how big 13 or so feet actually is later on.
Those are my thoughts. A poll is a great idea!