I heard that a lot of people play WoW and its really fun. I thought of buying it however I'm confused about something. If I'm a new player, do I just need to buy the cataclysm or do I need to buy all the expansions to get to cataclysm? Because I read somewhere that you need the previous expansions to get to catacly. Or if I buy cataclysm, would I get all the previous expansions with cataclysm like death knight and so forth too?