They're like apples and oranges, but if you're looking for something to buy then I would choose xbox live, unless you don't have any good games to play multiplayer with. Then I would choose WOW.
I agree with LordBob, because those are completely different types of things. WOW, is a game, and Xbox Live is a system that you can play in. If I had to choose I would say Xbox Live because even though WOW is really cool, I just think it's too time comsuming for me. Oh, and LordBob I don't think that they are like apples and oranges because both of those are fruits. If we were to compare them to something it would be apples to an apple basket lol.
I'd say Xbox Live, if you want to play a variety of games. WoW will take over your life, and there are a butt load of private servers that let you play for free, so just use those and download the installer from the website if you want to play WoW.
wow gets really boring really really fast...and its like for people hoo like to sit in a chair all day...xbox live is a limozene with many varietys of games and WoW is a monster truck u no wat i mean? lol wow is cheaper xD but its a monthly pay