Specific chains/stores are going to be a highly personal preference (although I'll put my vote in for Panera, which works really well at a Supercharger timewise).
If I were to rephrase the question as what amenities would you consider important at a Supercharger, my answer would be (in order of importance):
- 24/7 restroom
- Trash cans & window squeegees at the stalls
- Coffee / drinks / snacks available for individual purchase...