Yoga's great, (1-4 times a week depending on schedule) but it's far from optimal as cardio, weight training or flexibility training. It beats being a couch potatoe by miles but it's best seen as moving meditation not a complete fitness regimen.
Or swimming --- excellent for RSI, cardio, working out all your muscle groups, learning a useful skill, low impact, easy to keep going into old age, weather independent, no crossfit mentality. And you can easily pop into the sauna and steam room.
