I just wanted to make a make an argument against including MP3 bitrate information. While I know I'd greatly appreciate it, as would most of us users, it seems kinda dangerous.
Trading music via a peer-to-peer tool is legal suicide. Hence, music-specific clients like Napster, are a bad idea. By allowing the sharing and distribution of any material, not just music or other copyright-entangled mediums, there seems to be at least some argument that the client isn't a tool whose purpose is to aid copyright infringement - it's a file sharing facility whose danger is no more inherent then a network file share.
By parsing and displaying metadata specific to, say, music, that argument seems to be severely weakened - you're providing enhanced support for trading copyright infringing material.
'Course, in lieu of actually putting in the support yourself, if you provided us with some sort of plugin' system. I'm sure some of us more "industrious" users would be willing to take the hint.