I use SMF Media Gallery on my site, and it has support for these files by default:
Allowed File types:
* Image files: bmp, png, gif, jpg, jpe, jpeg
* Audio files: mp2, mp3, mpga, ram, ra, wax, wma, m4p, m4a, a-latm, ogg, rpm, mka, wav
* Video files: 3gp, 3g2, avi, mpg, mpeg, mpe, wmv, mxu, m4u, movie, qt, mov, rm, rmvb, rv, flv, f4v, mp4, m4v, mkv
* Documents: txt, rtf, pdf, xls, doc, ppt, docx, xlsx, pptx, xml, html, htm, php, css, js, zip, rar, ace, arj, 7z, gz, tar, tgz, bz, bzip2, sit
* Multimedia archives: zipm
I added support for FLAC by request, as my co-Admin says it's used a lot in the UK. Given that the above lists the most common types of files, it should help you in deciding just how many you wish to support.
Hope this helps.
