Hey Deb, specify what your goals are. Yoga can be anywhere from relaxing to taxing. I suscribe to the latter. I have Bryan Kest's Power Yoga and Sonic Yoga with Jonathan something or other. I always felt they worked me out pretty good.
What level are you at?
Have you tried yoga before?
Do you want something that's more an athletic stretch? Power yoga that will make you sweat? A nice, calm stretch?
I am completely new to yoga and got the FIRM yoga. It was very doable, and did not use any fancy yoga terms-with excellent cuing. If you're just starting, it's 30 minutes and very good.
I love Power Yoga by ROdney Yee and Brian Kest 1,2,3 and Total Yoga for overall yoga experience! Total Yoga is the most functional video I have ever bought!!!