The way XBMC works is the "Artists" list is populated using the "Album Artist" tags from the MP3. They also have an option to hide artists that only appear on compilation. I'd really like to see this implemented (at least as an option, for "Artists from Album Artists"). Hopefuly 3.0 isnt too far, cause this is a big annoyance for me. Having to maintain a properly tagged (with MusicBrainz Picard) library and a duplicate library with "simplified" artist tags so that i can copy it to my phone (using a 64gb sdcard for music, full).