In my opinion, World of Warcraft is definitely one of the better MMORPG's out on the market. It's pretty fun to play, and the beginning few levels are really easy; someone who has just installed the game would log on, create the character, and their interface would already be sufficient, self explanatory, and better yet, it comes with tutorials.
That isn't to say that only noobs play the game, though.
I've been playing it since it came out, and i still haven't totally explored all the areas, for instance: what is Uldum? we just don't know. WoW is huge and immersive.
If youve played the past warcraft's such as RoC or TFT, you'll definitely want to buy this game, and, at this point, chances are someone you know is already playing it.