I work out at 5:45 in the morning. I find it gives me good energy throughout the day and then when I'm done with work, I'm free to do what I want. I work 45 minutes away from home so if I were to try to go after work I wouldn't be done til after 7:30. And that would lead to an unhappy wife, and as they say, happy wife, happy life!
And for a shameless plug, I couldn't do it that early in the morning without the help of my trusty Powermax