Tagging mp3s

I am so spoiled to Picasa. Thank you, Google.

I spent a bunch of time organizing all of the photos on my hard drive. Tagging everything by year, people/animals/places in it, and occasion, where applicable. So now I can search for all photos containing Jeremy and Krissi in 2006, or all photos that contain Jason and John, but not Jeremy, or Christmas photos from any year. It rocks.

So.. why can't I do the same with my mp3s? I've got a ton of music, and, yes, I'm aware that I can make playlists. But I dont want to make playlists. I want to sit down and type in "industrial hard metal -metallica" and get anything that I've tagged as industrial or hard or metal, but that is not metallica, for example. Tags rule. And if iTunes can't/won't do it, I may have to take my music listening elsewhere. As I think more about it, the perfect solution would be something that I could tell it to do some autotagging, year, album name, artist name, song name, and then I could tag from there.