IMO the snowboard isn't as important as comfortable boots and staying warm. I would think any of the name band boards would be fine (K2, Burton, Forum, Ride, World Industries), and the others are probably good too.
Pretty much the only thing you need to worry about on a board is it's length. As a general rule of thumb a board should come up to your chin or mouth when stood on its end. In addition, a shorter board is usually used for freestyle snowboarding (tricks and whatnot), where a little longer one is more stable and is used for more all-around riding. I wouldn't worry about the width unless you have big feet, then you would probably need a board that advertises a larger width.
P.S. I wouldn't spend much over $300 on my first board