Originally Posted by froze
The single most dramatic improvement will be the lighter wheels and tires as others have said. Plus you can always transfer these to another bike.
But for commuting I disagree with the clipless pedals and shoes idea because a lot of commuters work in their shoes they rode in on, and clipless shoes will be very uncomfortable to walk around in all day-or you have to carry your work shoes with you in a backpack or pannier. Thus with regular pedals you can wear any shoe you want. You can get adjustable straps to help keep your feet on the pedals for better power transfer, with those any shoe will work.
Anything else you want to replace is up to you.
Actually, it's all up to him or her. ;-)
When I was able to commute by bicyle, I rode SPDs and stayed in them all day with no problem.
If he or she needs dress shoes at work, they don't have to be carried back and forth if they get left at work.
Sheldon "SPD Sandals" Brown
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