Depends.
For Melee, make a swordie. If you then make a Crusader, you can use Holy cross, or you can Grand Cross fairly easily.
For Magic, the Acolyte types can level VERY fast in the beginning using heal bombs on Zombie and Skeleton prisoners. The Mage class can also level fast with Soul strike, which is insta cast at max level. Try hunting undead with SS, just keep your distance.
