My God, I love ice cream.
First of all I'm a big fan of Ben and Jerry's the company, the factory in Vermont is awesome. When you go to a Ben and Jerry's in the northeast they sell a 20 scoop sundae called The Vermonster which is fantastic. All that being said, I hate the ice cream they sell in stores, it's crap.
Blue Bell is the best large production ice cream in the country, I'm happy they are back in Kansas after the mass murder thing.
Ashby's out of Michigan is also fantastic.
Blue Bunny here in Iowa is aight, pretty basic they have some great flavors like Fudge Almond and Cherry Chocolate.
The most underrated ice cream and flavor is right there in good ol' Kansas City. Belmonte makes the best mass produced Spumoni. Of course if you can get some locally made spumoni that would be the best ice cream you can find.
Baskin Robbins is meh.