Thing I worry about with books is the difficulty of transferring a written description and bunch of charts into what to actually do with my fingers. I've always had a good enough ear that I can often play something that sounds about right -- or make up something new that sounds fine within my limitations -- but if I saw how to do it more efficiently, I could probably do it better. That's why I was wondering about an instructional DVD -- though a decent teacher would be better, if I could find one and the time to go to regular lessons!
I remember watching the little bonus lessons from Zakk Wylde on that BLS concert video and thinking "Oh, so that's how you do that!" -- well, that and a lot of time locked in a room with a metronome ;) But it would be great to see explanations along the lines of "here's a common and useful lick, do it like that, no not like that, like this, right, now practice that until it's kinda fluid, OK, now here's a place you can use it, and here are some other things that work well with it ...."
The sort of thing that teachers are good at, if you've got one :)