For general use, if you were only going to buy one lens, I'd recommend the 40. The 65s are too bright for me in regular daylight. If you were to get a 3 lens set, it'd be 40, 65, and either the 80 or 99 (I have 15, 25, 40, 65, 80, and 99, and 2 sets of frames, all in the Panther Post).