Alley, yes, practicing definitely makes it better. My balance is not that good at all, but I do notice that when I'm regular and consistent, I improve. The older we get, the more challenging it becomes to maintain balance. Balance is one of the keys in preventing falls later in life.
I love the book for detailed instruction and benefits with regards to each pose. I refer to it often for that. To me, it's motivating. I don't think she does DVDs.
For an absolute beginner, it's hard for me to say which one. I absolutely love the Yin Yoga DVD. Yin Yoga is basically holding a stretch for 3-5 minutes or so. It gives you a much deeper stretch and has incredible benefits. My instructor told me that it's the closest thing to acupuncture. Both DVDs have sections for beginners. I would suggest looking at video samples of any DVD before purchasing. See if it's what you like. DVDs are quite subjective and tastes vary. Honestly, I love both of his DVDs and wish that he would come out with more.
http://www.myyogaonline.com/about-us/teachers/mark-laham - has quite a few video samples. The totalfitnessdvd site in my previous post also has samples.
Lots of people, especially those who are averse to yoga being weird or whatever, find that they like Sarah Ivanhoe - she has a few DVDs on amazon.
I'd love to get Ellen Barrett's Yogini Workout - simply because I love Ellen.
I heard about it on the Video Fitness forums. I haven't tried it out yet. There's lots of free workouts online. Tons of barre workouts also.
Heaven! I used to take a weekly Yin Yoga class on the beach. :)