Best Laptop for Creative Writing?

What is the best laptop for writing a novel? My price range is VERY low, 0 to 500. I will need hours of writing, and I will need a good quality screen for media editing and a very good Microsoft Word writing program. I prefer Dell. Something portable or very light. Nothing slow or bulky. I need something fast for research and installing programs. I LOVE the Inspiration Duo from Dell. I do allot of photo-shop and love the touchscreen. I have iTunes, and I present power points with my work. I know it's allot with a little budget. But, it's critical I have something by August. Any suggestions? Thank you SO much!