I am also at 6, and my favorites among those are the cherimoya and mangosteen. Both offer a physical challenge greater than does a banana, but are most assuredly worth it.
Of those I have yet to try, the monstera deliciosa is particularly magnetic, and the ackee is somewhat terribly frightening.
Also, I have heard of the stink of durian, rather similar to brettanomyces, if I recall correctly. And I have also forgotten what it is that will remove the smell form your hands.