My favorite potatoes to use are thin-skinned potatoes like Yukon gold. I usually opt to keep the potato skin on. You can always peel them off, but a lot of the nutrition is in the skin. Yellow potatoes like Yukon golds are a great middle of the road potato with an average starchy content. If you want a little more firmness in your potato salad, opt for less starchy, waxy potatoes like red potatoes, fingerlings or new potatoes. If you like a really mushy potato salad, then go for a high starch potato like a russet potatoe