So, what's wrong with iTunes? (or what more would you want?)
charliepark: It's absurd that I can't search in both podcasts and my normal music library with one search field. I have a number of podcasts from live shows (like NPR's "Live Concerts From All Songs Considered"), and if I look up an artist ("Neko Case"), I'll only get tracks from within the "Podcasts" or "Music" folder (depending on which one I'm currently in). I can't see any reason why search shouldn't offer a global search of iTunes folders.