If you don't need to run Windows based games, I'd recommend a Macbook. I've bought one three weeks ago and did some comparing with Windows systems, and found that while there are some cheaper Windows laptops, all of them have disadvantages, compared to the Macbook -- like shorter battery time, they aren't optimized for saving energy, they are bigger, they are louder and so on.

So Mac is not more expensive than a Windows laptop with similar specifications. Another problem with Windows machines is that you'll never know exactly what you're buying. I heard so many horrible stories from people who bought Windows laptops, like one part was broken, but could not be replaced due to incompatibilities, or new parts slowed down the system, no warranty, horrible service hotlines and so on.

With a Mac, you at least know what you are buying, because every computer is exactly the same, optimized hardware, optimized software, and -- which of course is a matter of taste -- Mac OS is visually and stylistically much more appealing than clumsy Windows, which will pop up these horrible speech bubbles all the time. Also, Mac's service is great.

You should also know that since Mac is using Intel processors, you can also install Windows as second system on Mac PCs, or Linux. So using a Mac would not even necessarily keep you from playing Windows games.