Yes Sidehatch, that is a great point that I should've made. If you can (and chances are, you can), bike to work. Not only is it built-in exercise every day, but you save money on gas and parking, your days of sitting in traffic just vanish, and you walk into your office having already accomplished something, which is a really nice feeling.
If your office is 5 miles or less from your house, you should strongly consider it. If it's between 5 and 10 miles, that's a haul but you should still give it some thought. Is there a way to drive halfway and then bike the rest? Bike to your metro station? Get creative.