there's also praat: http://www.fon.hum.uva.nl/praat/ (also accessable through http://www.praat.org) i have no experience with it myself, but from what i've heard (from musicologists) it's great.
tapestrea looks amazing (from the demo video), not because of the visualisation (which i'm not too interested in) but because of the sound possibilities. thanks for the link. carmen's idea [licker] sounds great too, but may be a bit over my head computer scientifically...
cheers, robbert
http://whats-your.name/i/licker.png is what i use , sure it uses more CPU than a C implementation, but its more flexible, and you can plug it in anywhere in your patch..