I have the four disc set (pure cardio, pure strength, yoga for the warrior, and bob's workout) and I like them all and have used them quite a bit since I got them (right now I'm doing a more structured program but will get back to bob's stuff later).
They're always resonably priced and have good replay value. AND my spouse even uses one of them (which really surprised me--he's not really an exercise dvd person).
When it comes to exercise dvds, the only way they WON'T work for you is if you don't do them. Even if you put them on and only do half (and do it half assed) you're doing more then you would just sitting on the couch.