Lots of great advice on this thread.
My memory is far worse than yours but I can tell you my combination of what was said previous:
Sleep is when the brain hard wires the days lessons. Lisitsa said when she has a problem area, after a night's sleep it is gone.
My problem is that sight reading has no useful purpose for me. When I play, it is on an unexpected piano. So everything has to be memorized. (If there was a way to read music from a cell phone, I would consider that. And you know, that can already be done with tablets - they have a little bluetooth boot pedal to "turn" the page. Is interesting because you could carry 100#'s of sheet music in a tablet...)
Advice to sight read will make the sight to hand process faster - but that doesn't make he recall process any faster. I've recently found that "concentrating" on the finger motion at faster muscle memory speeds can force the brain to recall faster. It is a strange technique but I believe it has merit.
Jazz guys, well forget them. They skills are mad. Singing each note is great but if you don't have that innate ability to "play by ear," it is an arduous task to develop it. How old are you and what is your life expectancy?
One remark on muscle memory and remembering the finger movements: What you remember are more than just the movements, it is the feelings in your fingers. If you hit a wrong note or use the wrong finger, it upsets the sequence, and you stumble and perhaps blow up. What is interesting is the faster you play you get feeling (forces actually) that are a result of inertia - the accelerating and deceleratin of finger/wrist mass on the way to the next hit. THIS IS ADDITIONAL INFORMATION which is why when trying to recall something, if you play as fast as crazy possible, you will experience greater inertial feelings which brings you closer to what you remember. CONVERSELY, if you play very slow, the loss of those muscle memory feelings will in many places will cause you to forget because you have remembered the place WITH the inertia feeling components.
I believe Gould used to practice at insane, ludicrous slow tempos before performing. And I'll tell you what, THAT is how to burn something into your memory. But keep in mind this is a method of reinforcing what you already have in your memory and muscle memory.
EVERYONE IS DIFFERENT: I believe more and more people are playing with music. Let's face it, do you really want to spend 5 to 50x more time learning a Ligeti? And there is also the reality you will be only able to take this so far given the amount of time you can spend and with what innate ability you possess.