Sand/Dupin was an important folk music collector. The "Bourree Aurore Sand" that she published is still played a lot in the balfolk scene. Dunno if all her folk music work has been published in convenient form - if not it should be.

Chopin complained that people kept appreciating his music for all the wrong reasons. What he was most proud of was the rhythmical structures he managed to pull off - complex multilayered textures with several different pulses going on at once. Listen to ALL the notes and you'll get it.

I have ended up with an enormous collection of Chopin interpretations by different players, there are so many different ways to look at it. There are several versions using instruments from his own time including a wonderful large set from the National Frederick Chopin Institute in Poland and I think recordings on his own piano were first done 10 or more years ago. The piano concertos also have some very different versions, my fave is Zimerman's where he conducts from the piano as Chopin would have done.