Firstly, i'm a teenager, but I don't play world of warcraft (i'm a girl, games like that really don't appeal to me). Your son is fourteen. I'm sure you don't need me to tell you that teenagers are a lot more mature than most parents think nowadays, so my suggestion would be let him have his own laptop and let him do what he wants with it. If you have a big problem with that, then you shouldn't be getting him a laptop?
If you trust him, you shouldn't worry too much. Every teenager has a laptop/time on the internet when parents aren't watching.
If you have any respect for your son, you wouldn't download one of those, quite basically, 'spying' programmes which tell you every site your son goes on, all of his msn chat conversations, all of his passwords and emails. Unless you tell him that you're doing that so he's aware. I would honestly be REALLY angry if I found out my parents were doing that to me, because it would mean that they're not respecting my privacy. You can't bring up a child knowing their passwords and reading their emails and messages and invading in their private life. I know you'll want him to be safe and you want the best for him, but there is a fine line. If my parents did that i'd never trust them again.
Talk to him about it, and bring it to his awareness. Under the parental controls on your web browser you can put mature content filters on, but a warning- my parents once did that and it blocked me from going on a maths gcse help website! God knows why that happened. You can 'unblock' certain sites (WOW site for example), and that should keep you happy.
Though if he's that desperate to do whatever he wants to do, us teens are smart, we'd suss out parental controls in a millisecond :]
So have some trust in your son.