Hard to choose a favorite I think. I'd say Peppermint, though its hard to find that out of the holiday season. Bubblegum is pretty good, but also not a super common ice cream flavor. Hell I recently stumbled across Root beer and Vanilla Float flavored ice cream that actually tastes spot on.
I love Tiger Stripe (Orange and Licorice) but I have not seen any for years I know that it is an odd combination, and most times I mention it I get frown-y yuck faces from those I address XD