Deppends on the server you're playin.
There are 2 dances that give 30 earth resist each, song elemental, elemental protection..
And if player wants, he can put even 2 parts of the set against earth.
If you can get more resist on you than the attack element, i recommend +duel element and water or holy on weapon. If there is no way you can get high earth resist, go earth.
This line of thinking (earth is always better, no matter what) is the one that got me killing a lot of dagers and archers. 2 parts of the set against earth and gg dager. His skills get weaker than +1 duel.