Chocolate Chip is the only ice cream worth eating. Specifically, Ben & Jerry's Vanilla Chocolate Chunk is the absolute best ice cream in the world. They discontinued it in grocery stores, but you can still find it occasionally at their ice cream stands in malls, etc.
Coffee, undoubtedly. But what's also great is getting French Vanilla (Not regular Vanilla) and sprinkling table salt. The large grain, not fine salt. The contrast of sweet/salty is unimaginably amazing. Alternatively you can smash bagged pretzels and throw them on.
In addition to chocolate chip ice cream, I occasionally do like an M&M McFlurry from McDonald's. Much better than the Dairy Queen M&M Blizzard.
I make my own ice cream at home sometimes and butter pecan is even awesomer when hommade. I also make strawberry. I also like black raspberry, though I've never made it before. Yummm