Have you considered bodyweight exercises before going to the bowflex? A good bodyweight regime will work many muscles. Also many yoga exercises will stress a lot of muscles.
When you're body is ready for it, I will second Millcreek's suggestion. Suspension straps have been one of the best workout regimes (for me) that I have done. While bodybuilders will tell you they are not good for building muscle (and they are right for building lots of mass), they absolutely build endurance muscles.
Also, they can be quite safe even if you're out of shape as long as you use the correct angles. My 91 year old dad even uses them, but from a very upright position. They actually help him with knee bends because they give him some support on the way back up. Once you're in shape to really utilize them, they are great for core and balance.