Anyone that has ever done any kind of role playing, such as Dungeon and Dragons or Shadowrun, knows the difficulty
When it comes to fantasy books, readers are often shifted the same way. Do you gravitate more to the action fantasy where there are epic battles between armies of orcs and men or the quest to find some mystic element that will change the world?
You're probably telling yourself that fantasy has both aspects, and you're right, but books are usually heavier in one than the other. Earthsea is definitely more magic than fighting, but I dare say many of the Dungeons and Dragons franchise books are more geared toward battle.
So it begs the question, what's your bag? Who would you be if given the chance? Aragorn or Gandalf? Would you like to slash enemies with your enchanted weapon or sit back in the distance and control the storms? When given the choice, I always chose the mage, and I love books filled with magic and sorcery.
A friend of mine would rather spend his time hacking his enemies in half, and those are the books he gravitates to. It's not that one is better than the other, just that we have different tastes. When you come right down to it, fantasy lovers can't have one without the other and aspects of both are integral to fantasy plots.