Do you know of any good filetype/mimetype icons?

If your startup is using filetype/mimetype icons, where did you get them from? Some sites use simple, yet elegant, icons (e.g.,: http://www.basecamphq.com/images/screenshots/files.png). The FamFam silk icon set has some, but they are small (16x16 pixels). Is there any other place from where good, yet elegant, filetype/mimetype icons can be obtained (either free or for a nominal price)?