I can't help you much on this one, i'm also trying to decide (gears or no gears). I don't have the hills you have (Madison WI) but it might be nice to have the option just in case.

Less then $500 you might want to keep an eye on craigslist (look for a bianchi) heck buy something cheap geard and play around with it. Ride in one gear for a couple weeks and if you think that is your calling then buy a conversion kit to single speed.