I' ve looked into boxing too KinkyFuckery. There is a place in my town where I can do one-on-one with a coach. Am putting it off though as i've already damaged a tendon in my right arm from the gym weights. Keep being told I need to lift heavy to bulk up - then I go and get injured and now can't lift heavy.
Must be quite therapeutic though punching out at someone in a controlled manner but I do hear it's excellent all over exercise.
Circuits 4 times a week at 45 minutes a session. Used to do boxing as well (would still like to do it now) and highly recommend it, you'd be surprised how much of a workout it is. Tried yoga last year and was the only young-ish bloke in the classes and couldn't manage a lot of poses due to lack of flexibility. First class I did there was a position where you lied on your back with legs curled up and hands on knees, then proceed to make circles with your knees while keeping legs up - 10 seconds in and a woman close by did a huge fanny fart. Suffice to say the 'relaxing atmosphere' left me instantly but didn't laugh properly until I left the class. Fun times.
Today is focusing on walking and lots of it. Maybe some yoga too =)