I just moved to Missoula, MT about 6 weeks ago from Salt Lake City for school. I live on the opposite side of town from the university and it is just under 7 miles for me to go one way to school. About a year ago I started riding the bus to work with my bike and then riding home a couple of days a week. With school this year, I have gone by bike almost every day. When I started riding home from work I put Conti touring tires on my 98 Cannondale F1000 mountain bike to turn it into a commuter (and now have a rack and panniers: hoping that fenders will be next if I figure out how to attach them). It takes me about the same time to bike the commute as drive it. Missoula is really nice as most of the roads have wide shoulders or marked bike lanes. Where my average commute speed slows down is on the MUP where I have any number of pedestrian and other bikes to pass. There are a lot of bikers around here and the biking infrastructure is quite nice. The Adventure Cycling resource is quite nice also. Missoula is also very flat which means I am not too sweaty on the commute and the hardest parts are headwinds (which I always have as I ride home everyday). One of these days I will make it about an hour south to look at a recumbent manufacturer.
I found this forum as a I became more serious about biking. I have used my bike more in the last year, than the previous seven put together.