Ostrich and Bison are the two things that probably top my list of things most people probably haven't eaten, but they are in no way my favorite thing.
A true Philadelphia cheese steak is probably the top of my list. If you claim you've had one and you weren't in/around Philly, then you were eating garbage. Granted that is a fairly famous food.
If I have to get into the more scarce items, spruce beer comes to mind. I love the stuff, but it seems you can only find it north of the border. It's literally like drinking a spruce tree