I have osteo and fibromyalgia and exercise is what helps keeps my pain levels down.
I walk, both slow and fast and took up cycling this year. I bought a stationary bike for the winter months and just love it. I do know alot of folks recommend swimming and I'm sure its good, but I don't have access to a a pool close to where I live. I also do yoga and it feels really good to stretch out my sore body.
I've just recently added very light weights and thats going OK.