Outside the realm of ice cream (because plain vanilla is boring), I am usually pretty fond of vanilla anything. Vanilla lattes and vanilla Italian sodas are the first things that come to mind.
I greatly dislike artificial fruit flavors like cherry and watermelon. Strawberry is probably the only exception here.
Chocolate is pretty safe, but also boring. I am wary of anything mint (except for peppermint mochas, mm!) or caramel flavored as 9/10 they are no good, but I love me a good mint brownie that does not taste like toothpaste. Hazelnut outside of nutella is not awesome.
What's your general go-to flavor?