There are two kinds of potato salad people: mayo and vinegar. At Sal's, we serve both, because I learned a long time ago that this is not an argument worth having.
The mayo version is classic — red potatoes, celery, hard-boiled eggs, a little paprika on top. The vinegar version is German-style with bacon, whole grain mustard, and scallions. Both are good. Both have their loyalists.
The secret to either one? Don't overcook the potatoes. They should hold their shape. Nobody wants potato mush.