My Alienware M17x R4 is not noisy at all. Occasionally you will hear the fan kick in for a little bit, but it's not very intrusive at all.
I couldn't recommend my laptop more to anyone who wants a great gaming machine. Mine is still going strong after almost 2 years and still plays anything I throw at it on max settings. Been a joy to use so far, but it was a bit pricey so I don't think I'd recommend it to anyone on a budget.
If price isn't an issue, buy a top of the line Alienware. You will love it.