Grumpy_Mike:
Using an FFT is not going to do what the OP asked for. Yes it will give you a nice display but it will not pick out a single note and allow you to light an LED. It will light LEDs according to the spectrum of the waveform. That is you will get a different display from the same note, depending on the not's harmonic content.
And this is perfectly fine. As long as it's "close enough". I do need to distinguish the differences between a lower and higher octave C being hit. And I think I can get that on a regular spectrum as one will generate more bass than the other. However, don't quote me on that, I don't have anything to test with right now. But this is also why I'm asking questions here before I try to actually make something.