I myself would suggest you get a macbook air and not a windows-based PC. i have found that mac laptops have greater battery capacity than any other brands. not to mention, that others are bulkier, more hefty and cant hold a charge as long.
We all know apple makes sleek stylish products. my wife's MBP if gorgeous, well-made, and has the classic attention to details/innovations that apple is famous for backlit keyboard and mag-safe power cable, but on the other hand, i have a windows machine that is half a year younger, cheap plastic-molded body, runs just fine and ran me about half as much.