Since I've collected many sound files and I had some time to kill, I wrote myself a little Soundboard script using Autohotkey. It scans a folder for sound files and dynamically creates a folder list + button list to click on. AHK Soundboard
Anyway, if you've interest, just try it and have fun.
Some hints: You can right click the folder list, buttons and playlist for different context menues. Shift+Click a button for quick rename. Playlist text files can be dragged into the playlist field. Autohotkey limitation: If the volume buttons have no effect, you've to run the script in Windows XP compatibility mode. And finally another Authotkey limitation: Other files than .wav might not be playable if the right codec isn't installed.
Attached's the compiled exe, including the pretty chaotic AHK source and some audio files to get you started. Tested under WinXP and Win7x64.
And here's my full collection of sound files... about 3800 files (180 MB): http://tinyurl.com/423je8v