I've also enjoyed getting into the habit of early morning exercise. First of all, it's pretty much the only time it is bearable to exercise outside in the summer. When I arrive at the Grant Statue at 6:30am, the sun is rising and casts a beautiful pink glow over the Capitol. By the time we finish running, the sun is already hot and I am glad to be finished for the day. Secondly, I feel more awake and motivated to eat well for the rest of the day. Thirdly, morning exercise allows me to be able to meet a friend after work, run errands, or go home and relax without feeling guilty about not working out.
And finally, to close with a quote by the man whose photo is on the $100 bill: "Early to bed and early to rise makes a man healthy, wealthy, and wise."