I need so many LEDs because I need an 8x8 button/led combo matrix (like the monome) plus extra status LEDs and buttons for miscellaneous stuff. I don't know what LEDs to buy though. Not sure whether I should just go with the cheap 25pc LED kit from Sparkfun to save on shipping, or whether or not it would be cheaper to get stuff off Mouser or Digikey. I also don't really have a good idea of how bright certain LEDs are going to be.
Also, I don't really understand what benefits an LED driver chip offers over a register. Is it just built to accomodate higher loads? I guess the simplest explanation of the project is that this is going to be a whole lot of LED/pushbutton pairs so that I can adjust and monitor the state of my live performance software quickly. The LEDs need to be bright enough to be clearly visible in moderate indoor lighting.