Actaully Throman's description also fits guitarists quite well. (I am one, so I'm allowed to say that). Actually I've always considered it to mean someone who is interested in music and music technology within the consumer audio realm, whether that be stereo, home theater, car audio, or some other niche. The term has some negative connotations in part because it implies a passive hobby, typically associated with the rich, which are always an inviting target. And also because so many audiophiles harbor beliefs, regarding the "special powers" of equipment, that border on lunacy to "normal" folks.