Mine would have to be Edy's Cherry Chocolate Chip... before I discovered that I used to be a Mint choco chip/cookie dough lover... I still like them... but thats my favorite!
Actually there is beer flavored icecream ^^ Down the street from me is a dairy that makes their own icecream.. adn beer is one of their most popular flavors ^^
Authentic Italian Gelato. Once you go gelato, you can't go back. I doubt you'll be able to find it (if you're outside of Italy or the West Coast) but anyone who is familia with Gelaty d'Italia's "Pistachio" will swear by it.
My favorite has got to be Ben and Jerry's Cherry Garcia. Mmm that stuff is like crack to me. I can't get enough. Before that it was plain ol' Black Raspberry.