Robin, everything that I have read says there is no universal best for everyone. So much has to do with where you're most prone to experience a fracture as far as frequency to specific body area. I have read that where you feel you need to increase the density most is the area you should exercise more frequently with weight bearing activities.
After reading that, my goal in prevention was just to increase the number of activities that used weight bearing and to challenge my body. As far as cardio, walking over swimming, hiking over biking, etc. However, I don't think they mean choosing exercise you don't enjoy. Obviously, moving is what's important.
I still enjoy full body workouts but playing around with splits ( whether single body parts or upper and lower) to increase the challenge. I am also dusting off those step workouts ..even with just the platform causes that stomping action for the legs.
I no longer avoid all impact either...I make it lower impact but do find ways to challenge those hips and legs with balance and some impact.
I hope someone who has experimented on themselves will post and offer some of their experience.
P.S. I love your signature quote!!