PILATES!!! It has changed my life. Pilates has slowly given me a core strength that supports my whole body. It supports my yoga practice, my hiking and my daily life in a way nothing else I've found.
I go to a class twice a week and then do shorter bursts (well a sort of pilates/yoga/freestyle combo) throughout the week. Anyway, massive fan of pilates here
I like to have a brisk walk most days too (preferable up the hilly lanes round where I live).