Very good discussion so far. Very good points presented !
T4D is right. You get a list of notes that sound tasty in your mind. For example: I like playing over minor chords in slow ballads. Some of my favorite intervals against minor chords are: 9s, 11s, 13s, min 7s. So if you know the notes on the fretboard, you can find the notes quicker. You must already KNOW what they sound like before you play them though.
Another great not for me is the 5th. Eric Johnson uses a lot of the 5th. You can use the 5th against any chord because its neutral in nature, BUT at the same time not as obvious as the root. My top pick for resolving phrases with chord tone targeting.
Memorization of the fretboard is something i'm trying to do as well. I'm combining the octaves approach with the C major scale approach. And also trying to memorize it in chunks of the neck. But still a work in progress.
One of my favorite things to do over a set of changes is to stick to a basic pentatonic scale. Then you pick a tasty note like a 3rd , 5th or 7th and play it on a chord change (going outside the pentatonic scale sometimes). What that does, is it SAVES that note and gives it extra emphasis. This works good, because pentatonic scales have 4 strong notes and 1 week one, whilst diatonic scales have 2 more week notes. So you can be safe and play pentatonics, going out of them only at certain times.