I'll get into this issue a little more when I put together a glute/leg training thread in the Women's BB section, but one thing for sure - DO NOT waste your time in the gym on those stupid abductor and adductor machines...you know, the "thigh master" machines.
The abductors and adductors are small muscles that can be worked sufficiently through compound and power exercises that work bigger muscles in the legs. Just by adjusting your foot position a little bit when squatting, or going deeper in your walking lunges, can burn the hell out of your inner and outer thigh. There is no need to spend your time in the gym sitting in the inner thigh or outer thigh crunch machine...you can get a lot more bang for your buck from bigger exercises that work the larger muscles in your lower body at the same time.