I ended up writing my own Windows application to audition my 15GB of drum samples. There was no way I wanted to change the folder structure they were in, so I ended up putting this freeware Windows app together: SourceForge.net: Aural Probe
Basically it indexes all of your drum samples within specified folders (and subfolders), and then allows you to create categories based on filename + path criteria.
eg. The "Kick" category might show all samples that have "kick", "kd", "bd", "bassd" in the filename (and/or pathname if you wish).
You can just use the up/down arrow to audition the sounds, and when you find one you like, there's shortcuts to bring it up selected in a new explorer window, or copy the full filename to the clipboard etc.
You can also create favourites, which is really useful if you want to put together sets of different samples, eg. tech house, breaks, downtempo, etc.
I use it all the time, to be honest I'd have no idea how to quickly navigate 15GB of samples without it! (Which is why I wrote it!)