Not sure if these points were covered, but don't spend $500 on your first commuter. You can get a great used bike for around $200 or less. Spend the rest of the money on accessories like fenders, clothing, bags, racks, or whatever you find you'll need to commute comfortably. After a while of commuting, you'll really figure out what the right bike is for you, and you'll be glad you didn't waste $500. Also, don't just hop on the bike and go 15 miles. Even if your lungs, heart, and legs are in condition to do that, your butt is not. You need to break your bottom in slowly. Start out with shorter rides and work your way up.