It's pretty clear that spectral editing will be the next big thing in audio production. At first it will be expensive, manually intensive, and require high end computers. Overtime all of those will be mitigated, but I'd guess another 2 to 4 years before you can push a button and extract instruments from existing mixes (without a lot of manual intervention) in a consumer class product. Yes I have seen all the demos, overtones are the current problem
FYI, for just for looking at notes in spectorgrams, foobar does a really nice job (is there anything foobar can't do?).
View --> visualizations --> spectrogram.
Then right click in the spectrogram window for options like "full screen". Mesmerizing to watch in real time with the music.