I'm surprised no one has asked what you're going to use it for. This 3wt question comes up a lot (I asked it a few months ago). I agree with Zach in that 3 wts are usually for small waters; however I've heard some folks say 3wts are also useful where you need longer delicate casts, hence a longer rod. I say for these instances just use a 4 or 5 wt. and if not then you're getting into specialties.

So what are you gonna use it for?