You should use the so called fluid or Elastic layout, in short instead of using fixed width, e.g #wraper{width:960px} //Fixed
you either dont define width or use %
#wraper{width:90%} //Fluid
or elastic in which case you define your width in em, and will change width as the text is enlarged
#wraper{width:40em} //Elastic
All methods have their cons/pros and there is a lot of argument which is correct.
I personally think that it all depends from your design, all designs require different layout, which might be fluid or fixed, so I would say there is no right or wrong layout.