You have to consider your needs and wants-
1. Consider size and weight. Do you want to carry it around a lot or just use it in your room? A netbook will be the smallest and lightest, but doesn't have much power and the screen is hard to work on.
2. How much power do you need, i.e. are you going to try to play elaborate games on it or just use it for school work?
I recommend a 13" ultralight if you are going to carry it around much. These are much more powerful than netbooks but not much heavier. They also have good battery life and the 13" screen is much better for working than the 10" netbook screen. They aren't more expensive than midrange notebooks but they are more expensive than netbooks. I have one of these, a Toshiba T135. I don't know what their current model is but Toshiba, HP, Lenovo, Acer and ASUS were all making similar models a year ago.
If you need to play games then you will have to find a 14" or 15" notebook with better processor and better gpu. You can still carry it around some but it will be heavier and won't have as much battery life. And a notebook with a good gpu will be more expensive.