The MRs and I have been doing Pilates 2-3 times a week since Christmas and I really notice the benefits, better core strength = easier getting up and down from the floor, better posture, helps on the bike with flexibility and getting over/around stuff and generally feel better. I can even see my abs!
We started with a simple DVD and have moved on to the more advanced ones.
Check out stottpilates.co.uk (google stott pilates if that is wrong)