I have done P90 Masterseries, P90 Power half hour (very good), P90x, and Turbo Jam.

The MOST fun was Turbo Jam. It was easy on my knees, and it makes cardio fun for me.

The P90 Power half hour is very good as well. Its not hard on the knees and not nearly as intense as the other series.
Currently Loving:
Shampoo: Giovanni 50:50

Conditioners - CJ Strengthening, CJ Beauticurls Argan and Olive Oil, CJ Rehab, CJ Curl Fix

Leave-in: CJ Smoothing

Deep Conditioner: CJ Hibiscus and Banana Deep Fix

Stylers - Tigi Curls Rock Amplifier, AG:Recoil, KCCC, Mop-C Curling Cream, Paul Mitchell Sculpting foam