Strawberry jam is my first choice, but I like them with grape jelly, too.
The original post made me smile, having been in a similar situation. I was in high school before I knew that pizza came in more "flavors" than cheese or pepperoni. My parents never gave us any choice, so how was I to know? Same with hot fudge sundaes. My father used to bring them home for us: Vanilla ice cream, hot fudge, whipped cream, nuts, and a cherry. Who knew you could pick your ice cream flavor? (peppermint stick, please!)