There is a special breed of player who's not content to level from 1 to 70 in the ordinary manner. Instead, they choose to place hindrances on themselves to create a more challenging experience. Gutrot of the European Aerie Peak realm is one example. He finally attained level 70 a few weeks ago after months of questing and killing creatures naked, with no weapons or visible armor aside from his trusty loincloth. His feat has made him a minor Wow celebrity and there was a huge party when he finally hit the level cap. Other players have placed different limitations on themselves, seemingly inspired by Gutrot. For instance, Gweryc and Kakita are both melee-only hunters while Noor is a pacifist, trying to reach the level cap without killing anything.
I've always been intrigued by this sort of idea, and have even made a character or two myself that had such limitations placed upon them. Recently, during the long dark night between patches, I got bored with my mindless and aimless farming and decided to create a new alt. I decided that this character would be a Draenei warrior, but that he would only fight unarmed, with a staff or with a throwing weapon. I also decided that he could only wear cloth or leather items. I suppose my idea was based somewhat on a sketchy notion of some kind of fighting monk.