Best ID3 Tag Editor

I'm looking for software that will essentially allow me to mass edit ID3 tags, assign album art, etc. I have organized my library in Explorer instead of in Traktor or iTunes. I figure that this is the easiest, most cross platform friendly, way of organizing music. I despise using iTunes because I feel like it adds an unnecessary step to the process of organizing, cataloging, scanning and playing music.

I'm a Nazi about keeping names organized, free of links, etc. I can't clean up the ID3 tags themselves from Explorer in Mac, though. I need something that will get to the bottom of this.

Does anyone know of a good ID3 tag editor that YOU have experience with? I've tried a few out that I've found online but they were all nothing to call home about/were too costly/didn't work well.