As far as technique goes I would definitely recommend "Mechanics for Speed". It has a lot of useful exercises that gave me ideas to trigger my own mechanical/symetrical stuff for development of my hands (which is proving to be amazingly useful right now). If you can get a hold of Joe Satriani's Guitar Secrets (it goes for like 10 bucks in Amazon) it has that and a bit more on the things you want to work on, like intervals, ear training and improvisation. Since those are mini-lessons you can get a lot of mileage out of that book (I seem to find new stuff every time I look at it, and I've had it for a couple of years now).
All the books in the Leavit series are great for sight reading and you can get some interesting exercises (chord etudes specially) out of it.
A word on sight reading: When you do it, you need to read. I know it sounds obvious, but a lot of students tend to stop at every note and try and figure out and then move on to the next, that will lead to memorization and it's not what you want. You need to look ahead and simply identify the notes as you are going. If you are new to notation I would spend a few months working through a beginner's book like Mel Bay book 1, Hall Leonard Method 1, even those fast track books or the progressive method will do (I think alfred has come up with "essential elements for guitar" as well) the point on that is that the stuff will be so dead-brain easy for you that you won't need to figure out how to play it and you can focus on note identification on the spot. Once you have one or two months of that under your belt then tackle the Leavit Books and approach them the same way, just play right through the examples. You will mess up in the beginning but as you move farther and your reading gets better you won't make as many mistakes. It is imperative that you spend enough time in the "boring sections" of the book, where you are playing only in half notes or quarter notes through fairly predictable sequences, make sure you internalize those and they will help you later in the book. Other than that, simply follow Mr Leavit's instructions. He is a much better teacher than I am (I mean he was chair of the guitar department in Berklee for a reason

).
Anyway, I hope this helps.
-Jorge
I am glad we play guitar because: