If you are leveling a single toon and you have a bunch of high level guys to help, I would quest boost.

Basicaly run quests with your rogue and have all the shamen on follow but not grouped. Tag the mobs you need for quests with the rogue and blast them down with the shaman. Use the shaman in a group when you have quests that involve instances. But with that much firepower behind you, it will go fast. This is what I did with my original group. 1priest and 4 mages. I got to level 68ish and needed a tank. I dropped a mage and powerleveled a paladin via quests with the other 4 nongrouped on follow. It went very fast and collection quests were a non issue as well. After about level 30 I just grouped them all, Even though I took an xp hit on mob kills. It was just way faster to steer with the paladin and mass blast with the mages and priest. 3x arcane barrage pretty much 1 shot anyting in vanilla wow.

Just use one of the many online quest leveling guides like Jame's or what not and you will be 60 in no time.