Personally I started cycling to and from work and it works really well for me, 14km/9m per day, my endocrinologist and dietician recommend at least 30 minutes of cardio per day but I end up taking 20min to work and 25 home.
No parking fees, no insurance, no traffic and it's faster than driving or taking the subway. Sooo, in my case I save time off my commute, get healthy and save money, win win win.
After about 2-3 weeks I finally got rid of that tummy blubber that had refused to surrender to any diets. My butt is firmer and better formed, so are my thighs and tummy, I have noticed my arms getting firmer and stronger but not bigger, all in all I think it's a very good option for those of us who hate the gym. Other things that should fit the profile for MTF workouts are skating, skying, running and walking, get those big leg and butt muscles burning and building.