Let me clarify my opinion about practicing yoga with videos. I believe yoga should take into account your body's abilities, limitations and experiences. Videos do not necessarily address everyone's needs and weaknesses. However, a video is useful when the practitioner or viewer has enough basic knowledge of yoga and their body to make adaptations or variations according to his or her needs. So long as the yoga practitioner or viewer listens to his or her body, a video or CD may prove to be helpful.
Unfortunately, I have found individuals that have used yoga videos are discouraged. There are so many types yoga and teaching methods that it is costly to sample yoga DVDs. People end up throwing in the hat before finding a video or series they enjoy.
If you do find a video or CD that you enjoy and meets your needs, remember to find balance in your practice. Even though yoga is about balance... doing the same practice, the same way over and over again will create or further current imbalances. Mix it up and have fun with your practice.
As always I encourage you to practice yoga by checking in with your body to see what is congested or uncomfortable. Allow your practice to unfold releasing congestion by practicing one or more poses from the different categories - forward bend, backbend, inversion, standing, balance, twists, etc. Don't hesitate to pause the video or CD to add your own pose or sequence. Feel free to substitute poses for what it is suggesting.
Remember it is YOUR practice. Ultimately honor your needs.