QUOTE(Frank Bicking @ Dec 20 2007, 13:12)

Apart from excluding certain file types as already mentioned by Matt, no.
I almost suggested changing the list of library folders (also on Preferences | Media Library) then remove dead entries, but I wasn't sure what happens on rescan. Are existing library entries for files that are no longer part of a listed folder removed? Even after changing the folders around, remove dead entries wouldn't really be appropriate, it seems, because the files would still be there. I also noticed, a long time ago when I narrowed down my library folders, my playcounts were lost. I'm not saying this was incorrect, just something to keep in mind for the OP (ratings could be lost too). Thanks for your insights Frank.