I'd been wanting to write a sound effects database for awhile because I hadn't been able to find anything Windows-based that is reasonably priced (like under $50). I finally got around to writing my own, Splat.
The audio file reading is done by libsndfile (the same thing that Audacity, Supercollider, and a bunch of other audio apps use), so it's able to open and play back a dizzying array of file types and formats. Playback of the sounds is very quick, so it's easy to browse through a bunch of files. Unfortunately no .mp3 or .ogg playback support yet, although you can still add those files to the database. I may add .ogg at some point, but .mp3 playback requires a license from Fraunhofer, and there's no way I can afford that. However, you can use the "Play in Default Application" button to play an .mp3 or .ogg file in whatever you usually use to play .mp3 files, such as Windows Media Player or Winamp. It seems worth noting that Splat is designed for archiving audio files for sound designers or composers, so it can play back high bit depth and high sample rate files that applications like iTunes can't play. .mp3 or .ogg playback is kind of a low priority.
I haven't written any documentation yet, but basically, you create a new .splt file, and start adding audio files to it. You can do that either one by one using the "Add Item" section, or you can add a whole bunch of files using the "Add Multiple Files" section by clicking "browse", and ctrl- or shift- clicking the files that you want to add. Or, you can just select a directory, and have Splat add all of the audio files in it. You can modify file information just by double-clicking on the field that you want to change in the "Sounds" area. Searching is done pretty much as you would expect, and the "Open Containing Folder" button will open the folder in Explorer of the audio file that you have selected, and highlight it (pretty much exactly like the Firefox "Open Containing Folder" function. There is no "save" or "save as", as the database file is updated immediately when you add or change an item.