I recently got a new bike and just started commuting regularly. My commutes (6.5 miles each way) have been lovely. Today the weather was cool. A bit of fog in the morning but clear with some sun this evening. My route is mostly on city streets. The only problems are the drivers who seem to want to prove a point by gunning their engines as they overtake me.

I agree with the bike heals comment. Some mornings I'm tired and have no enthusiasm for riding to work. But I climb on the bike and start peddling anyway. By the second mile I feel great.