I may be wrong but if I remember my beer books correctly Crystal 40L is the "standard" when a recipe doesn't specify and I don't think "American" in the front makes any difference.
Next Up: Auspice Irish Red
Primary 2: Slobtoberfest
Secondary 1: N/A
Secondary 2: N/A
Recently finished: Kolsch Batch #2, American Wheat, Kolsch, Rye Beer