* Some sort of external microphone and audio interface. I use an Edirol FA101 when building this. I haven't got it working well with the Mac's internal sound
* OSX - unless you want to make the GUI stuff cross-platform.
* Add analysis of amplitude envelope, only uses timbral analysis at the moment which while quite good it needs amp.env. comparison to be really intuitive
* Add ability to scan and add samples via GUI, from any location