I can't say I am a huge fan of strength training videos.
The keys to effective strength training are:
* slow and controlled movements
* good form
* using a genuine challenging weight
Basically, ST is a very self-paced activity, and you should be focussing on how you do each movement.
With videos, the tendency is to focus on the screen, and not your body. Also, most instructors to tend use lighter weights (because of the need for many retakes) than are required for effective strength training.
Personally, I prefer the demos at www.sparkpeople.com/resource/exercise_demo
That said, videos are a good way to see the full movement and the correct form.
Perhaps one compromise would be to look at the instructor and learn the form, then hit pause and do it yourself, rather than trying to "follow along" as you might for a cardio video.