In undergrad, I kind of wanted a bike, but never followed through. So I decided to change that in grad school. It's a 4 mile round trip commute, just about, and I'd much rather ride than take the car, search for parking, etc. Today, I had to go back and forth three times, which resulted in about 12 miles of cycling. Tiring, but fun. I have a U-lock and a cable lock, but I'll probably only use the U-lock in the day time, and use both during my night class.
I love listening to my iPod when riding. I listened to it when walking everywhere as an undergrad, so it's neat to be able to do the same now, but on a bike. I've got a tape deck set up to allow me to do the same in my car, but so far, I haven't driven the car anywhere. Still waiting for bad weather. I also use the bike on trips to the grocery store, which is about 5 miles round trip. Overall, I'm pretty satisfied. I see lots of riders, and the racks by my campus building were pretty full the three times I came by to park.