I am by no stretch of the imagination the worlds most avvid World of Warcraft player, but I've dabbled a little and when I have nothing exciting to play on my Xbox 360 it's a great filler. A monthly subscription will also only cost you just over R100, which is great if you're a little strapped for cash and can't fork out R700 for a new 360 game.
One of the only issues I had with WoW as a casual player was that I couldn't really complete any of the dungeons, or instances, as I didn't really know...