In reply to Gibson:
Depends how wild/civilised you want to be. For proper campsites, I'd probably reccomend Fidden (pron. Feedjen) a mile or so south of Fionnphort. This is a a busy family campsite with a good atmosphere. West Mull is much better then east Mull in every way. Ross of Mull granite landscape is fantastic - great walking, and handy for climbing on Erraid, and limitless bouldering should you want such things..