Level 90 boost, follower iLevel, world bosses

Does anyone else still have a level 90 boost lying around? I haven't been able to figure out what to do with the one I got through my Warlords purchase, so it's just been sitting there. World of Warcraft(EUR) Right now I'm torn between using it on my Monk (the only tanking class I don't have at least a 90 of) and my Shaman (one of the only DPS classes that has intrigued me enough to get past level 20 that I don't have maxed yet - I'm also considering healing). Any thots?