Once at the store, you will find a number of varieties. Select based on the description on the store tag. Favorite tomatoes are: Better Boy, Early Girl and Celebrity. These are all-around good for flavor and uniform size.
Peppers will be based on the amount of "heat" you want. Bell is low, banana adds a bit of punch, Jalapeno takes it up a notch, with cayenne, tobacco and habanero bringing on the heat. NOTE: peppers generally can withstand more dry soil than do tomatoes.
This year, I grew 6 different types, from Bell to Habanero, and dried them for use throughout the year. One of my favorite recipes is Pimento Cheese. It is now a family staple and ohhhh so good and creamy.