what do I need

Apple will cost you 3x as much as PC. Since they use Intel and nVidia graphics now (like PC) and Realtek audio you are paying triple for the operating system. If you got that kind of cash, cool. Most people do not. A cheap laptop with 17" screen is a good way to go since you get a good screen size. I currently prefer Toshiba but they are all the same at the end of the day. IF you shop you can find one for 5-600 where Apple will cost you triple. Yes, triple. I would suggest bigger drives and a more expensive laptop for most but you just need the basics. For example:

Toshiba:
http://www.newegg.com/Product/Product.aspx?Item=N82E16834214867
Hewlett Packard:
http://www.newegg.com/Product/Product.aspx?Item=N82E16834158573

All you need for the basics, should last you for years.