Waterball is a great skill and should not be neglected even if you hate it, it is the most powerful single target spell in the game.
As for tome cardings, there are pretty much two main ones.
DDT For those who like to melee.
DDDrake for those who like to cast spells.
I'd go for DDDrake since melee builds generally require a good amount of gears and experience to be able to pull them off properly