I have all of the Turbo Jams and I would have to say that my favorite is Kickin Core - one of the new ball ones. Love the music and the workout. Second would be Fat Blaster. In Fat Blaster you do 4 turbos in a row - actually 8 turbos in that you do/learn one in low impact/intensity - then do the same one in high intensity. The 30 mintues goes by incredibly fast. Third would be Kick, Punch and Jam - it is more athletic, less dancey and again - awesome music, moves etc... Total Body Blast is fun and different in that it is more of a circuit workout, and I have DOMS after doing it.
I do like the 20 minute workout to get in some quick cardio before doing a weight workout.
You just cant go wrong with Turbo Jam and the music - it is SO awesome and goes with the moves so well. I woke up in the middle of the night the other day with the music running through my head. If I am not feeling doing a workout - all I do is start to think about the music and it gets me moving and ready to do it.
I do most of them these days with the weighted gloves that you can get from beachbody as well - it really adds that little bit more so you really feel worked when you are done.
HTH