Hi Gailerina,
Joining Tai Chi was for meditative reasons, but it is also a martial art, I understand, and is helping me express myself too, since there is a movement outwards, which I as an introvert don't normally manage to express myself successfully, and feel frustrated. I'm also fulfilling a dream, since taking this is something I've wished to do for so long, and have been unable to convince myself, because of time constraints, etc.
I've never taken boxing, but when I took a contact martial art as a young man, I was in the best physical condition of my life, and had a great deal of energy, as well as at a physical weight unmatched in my adult life, losing 30 pounds in 30 days. Boxing is something I admire at the gym and I might consider since my instructor also teaches karate there, and there might be a transition I could make. It might be hard on my body now though.
Is taking boxing something that's interested you in the past, or that friends have tried?