Soundplant sample player: http://soundplant.org/
For windows and Mac. Made for theatre sample triggering. I have an early version of it when it was free - the new version is free/trialware. $35 for unlimited version:
"Soundplant is offered as a free download at http://soundplant.org/
which includes a 25-launch trial of the registered features. In unregistered mode it is free for non-commercial use and limited to playing uncompressed 8- and 16-bit wav and aif files. The registered version (USD $35, or a $28 upgrade from previous versions) allows loading all sound file types including higher bit depths, compressed formats like mp3, mp4, flac, wma, alac, audio from video files like avi, flv, mov, wmv, and more"
**EDIT** just downloaded the latest version - it is VERY good! Freeware mode is fine, can only use wav/aif files 8/16bit/44k, nag screen every 5 launches. Fine for me.
Casio: FZ1, CZ101, PG380, VZ10M, SK8, SK60, RAP10, DP1 drums, DH100, CDP200, DM100
Yamaha: TX81z, TX802, SHS10, DTXv2
Roland: SH101, DR660, MS1, PM16, TR33
Others: Korg MicroKontrol, ES-1, Alesis MMT8, Emu ESi2000 & card reader, BCR2000, V-Machine