The best 2h weapon a pally can get starting from level 20 is Verigan's Fist :
http://wow.allakhazam.com/item.html?witem=6953
It is a 2h blue hammer with 25dps and 7 Stamina, +12 Spirit, +6 Intellect bonus. The item is a reward of the The Test of Righteousness quest, available for paladins only. The quest requires the Tome Of Valor quest to be done first and you can take it from Duthorian Rall. I did the quests solo at level 26, but the last part is very tricky. However if you have some powerfull friends you can easily do it. And the reward is totally worth it. I am now at level 32 and still using the hammer