Although the Core Max DVD is good, IMHO you should get Muscle Max first, since Core Max is . . . well, only Core, and MM works the whole body. AND, the core routine on MM prompted a thread of mine a few months ago on the Ask Cathe forum called "Liar Liar Abs On Fire" - you get the idea.
Save Core Max as a potential stocking stuffer and get MM now.
A-Jock