Depends on what type your looking for, the best one I bought and use is the new ministry of sound 2012 dvd, i think its great.
Its broken down into easy little 20 minute sections, Toning, dance mix 1, dance mix 2 and bums n tums, and you can do as many or as little sections as you like.
Plus its really easy,I have tried a few,Nell mcandrew, debbie rush, davina..... but this one has been the best for me and help aid alot of my weight loss.
I have also been told that the Jenifer Ellison dvd is very good! I may be purchasing that one.
Good luck!