Unless a recipe calls specifically for unsalted, I use salted.
PS I never use fake butter. When I was a kid, my dad (a medical doctor) was always on us about only using margarine. I hated the stuff, and would put butter in the cart whenever I was with my mom at the grocery store. Today, of course, doctors know (or should know) that margarine is basically poison, and real butter isn't bad for you.
