I am primarily a self taught guitarist in my own technique and style that is drawn from many other styles of playing. The experience I have found with books (I've never tried cds/dvds/tapes etc) is that you have to be creative about your exercises. The technique of a style is as broad as the musical spectrum. The same is with teaching. I've had several different teachers in all the styles of rock, jazz, blues, and classical. Each of them with a different approach to the music, this is especially evident in different jazz techniques, not so much with classical techniques. so the technique is only really applicable to whom you've been taught and by what your playing. my suggestion, if you want something to tackle, study classical, pop, and jazz theory and apply everything you learn to the guitar. it should keep you busy for a while.