I'd have to echo the above advice ... set a budget and then look around at that price to see what you think is a good deal, or if your not too confident, grab a few different specs and put them under the nose of a friendly computer geek.
I've just bought myself a Mac Book Pro over christmas, and I would say, if your not tied to a windows machine then Macs are a good thing to look at. They have everything you could need out of the box, run reasonably fast, and the operating system is a joy to use. Only grumble is that they moved the @ and " on the keyboard :P Plus the design of the things is very shiny and nice to look at

However they are more expensive when considered against windows laptops, so that may be a consideration.