id say a pally, you can heal yourself, tank a shit load of monsters with a minimal risk of dieing and from what i know there the most wanted tanks for dungeons and what not. you can do that or a druid, the druid is pretty much the same thing but in order to heal yourself you'll have to get out of bear form (tanking) making you have less armor and health, which MAY get you killed., other then that pallies and druids are the same on terms of being good starter
And if you dont know what tanking is, its when you can deal with about 3+ monsters attacking you at once and have a less chance of dying because you have better armor bonuses. Say you play a mage, mages can only wear cloth armor, which is the lowest armor in the game pretty much. Now being a warrior or a pally you can use mail at low levels, and then plate, those being the two best in the game which means they give more defence compared to cloth, therefore letting you take more damage and have a less risk of dying then say having 3 monsters on you while wearing cloth. Get it :\