Growing up, I always looked very much forward to summertime and my dad planting his beefeater tomatoes. Sometimes he'd say he was going to try a different variety, and then I would have to visit a nursery and pick out a couple of beefeater plants to raise on my own.
Didn't realize he was doubling his harvest without increasing his effort because he would plant something else, like squash or okra.
Anyway, my favorite summertime sandwich then, and now, was a thick slice of beefeater (or, today, heirloom) tomato between two slices of bread with mayonnaise. The tomato is generously peppered with enough salt to taste. Yummy!
The best sandwich I ever had "out" was when I was in college. A group of us would go into Asheville NC to a shopping center that had a placed called "The Rathskeller." They made a wonderful reuben on rye, and they served it with a kosher dill and a side of German potato salad. Hands down, that was my favorite sandwich meal ever. I still try to recapture that magic with a reuben order at various delis. Some are extremely good. None, however, have German potato salad sides to offer.