Check out a column called Play Evolution, by James Lantz. He write about "The Evolution of World of Warcraft". Basically he covers the many games within World of Warcraft. Things such as the exploration game, where you explore "secret" areas and every corner of the maps. There's ways to have fun with the fishing and crafting professions and a lot more.
You can’t beat World of Warcraft – there’s no such thing. There are no victory conditions, and you’ll never see a screen that pops up and says, “You win!” You may think that getting to the highest possible level is an obvious victory, but that’s not true for everyone. Some people are satisfied with hitting the level cap, but others want to beat every raid boss.
It’s perfectly feasible to imagine hundreds of personal goals, even ones as obscure as crossing from one capital city to another at level one, or camping an important travel NPC so no one can reach his hub. Because there’s nothing as simple as beating the game, every goal in World of Warcraft is completely arbitrary and set by each player to match his or her own desires.
Check out the full column here.