I suck at this and would love not to anymore, so I would love it if you guys would tell me the best books to read on it. Thank you.
Three that arguably should be on your list (there will be others but I don't know them): Story by Robert McKee On Directing Film by David Mamet Adventures in the Screen Trade by William Goldman and also just about any screenplay that has ever been written, preferably in its original form (that is, not a transcript of the finished film masquerading as a screenplay) I found Story invaluable as it covers ideas of what it is to tell a story, but with emphasis on doing so from a screenwriting perspective. It's not about basic formatting though. On Directing Film might seem an odd choice, but it offers insight into how a film uses juxtaposition of shots to build a story, which can be invaluable knowledge to have onboard when constructing a screenplay. Adventures in the Screen Trade is more of a memoir, but can provide a humourous insight into the workings of Hollywood (though it has to be said it's from an older age of screenwriting so may seem less relevant today).
I recently bought David Mamet's "Bambi vs. Godzilla", and didn't have a chance to read anything but the table of contents. It seems to me that he does have SOME technical pointers on movies, but I mainly bought the book for the man's cultural commentary about Hollywood, America, etc. I know this is not what you started this thread for, but it's something to think about if you'd like a book that goes beyond the technical. After all, if you're going to write scripts you'd probably want to know about the history of this profession, the arguments and schools of thoughts, etc. I think this would especially be interesting if the commentary is done by a man who crossed the political aisle and had seen both of them from the inside.
Save the Cat by Blake Snyder helped me developed my screenwriting skills. My IMDB How to Write A Movie in 3 Weeks!