Notation and Music Reading
Rock is a riff-based, pattern-oriented playing style. Reading standard music notation is not essential -- in fact, most of the musicians who are creating the music that you hear on the radio do not even know how to read standard music notation (staff). I'm not saying that learning to read staff is a bad idea... I read it myself. I'm only saying that if your goal is playing rock or metal, it's not essential, and its value in that instance is questionable.
Tablature is an alternate method of reading music by indicating fret numbers and strings -- tailor made for guitar -- and this is much easier and faster to learn. But tablature generally has no rhythmic (timing) information. So many books employ a combined staff/tab system that includes both. Some of my books use this system.
My core metal methods, however, cut right to the heart of things by omitting the staff entirely and fusing the rhythm information directly onto the tablature fret numbers. There are two big benefits of this: First, it takes up only about half as much space, so I can pack nearly twice as much music into these methods. The other benefit is that I don't have to teach how to read the staff within the method and can therefore focus on just what is crucial. (And the truth is that something like 90% of all guitarists completely ignore the staff anyway, when reading those combined staff/tab systems.)
On the other hand, if you are interested in jazz or classical guitar, learning to sight-reading staff notation is a must. Also, it is helpful if you aspire to being a session player and getting a wide variety of studio work. Furthermore, if you just want to take your guitar playing skills as far as possible, certainly reading music is a skill that you'll want to work on, at least in the background at the same time you are developing all other skills.
So, to sum things up, there are basically four different methods for guitar notation: 1) staff only, 2) tab only, 3) tab with rhythm info, 3) combined staff/tab. Advanced transcription books feature staff-with-tab, as do most rock instructional products published by Hal Leonard. My rock instructional products feature tab-with-rhythm-notation in many cases, although several also include staff together with tab . Many basic guitar methods include only staff, such as the Hal Leonard Guitar Method and the Berkelee Series.
And there you have it!