A past professor recently asked island (the information systems forum/community I participate in) whether he should get a tablet or a laptop for his teenage daughter. She's been asking for a tablet, and he wants a solution that will work for her for both play and for school and homework. It's an interesting question and very interesting topic since laptops and tablets are accepted for use in many high schools across the US. When I was in high school (2001-2005) using a laptop at school wasn't even a consideration. I wonder what kids will have in 30 years...

Here are my recommendations at around the $300 price:

Nexus 10
iPad 2
Windows Surface (with condition)

The Nexus 10 is going to be pretty ideal for this situation. I think a high schooler can very reasonably do their studying and homework on a tablet, with the exception of research papers and essays. For those he or she may need to use the family computer (or at least a keyboard dock), but I wouldn't consider that case enough reasoning to go with a laptop instead of a tablet, especially if they're already wanting a tablet. I have a Nexus 7 and I really like it for reading and for taking notes. I love Evernote because it's on every platform I could dream of using (web, iOS, Android, Amazon, OS X, Windows, and even Windows Phone, but not Linux AFAIK).

As another option I think you can get a 16GB iPad 2 in that price range, which would be a great choice as well. It also wouldn't be brand new, which may or may not be important to a parent. I know some would rather their teenagers have a older generation version of a project than something fresh off the shelves.

About the Microsoft Surface... if it were 1 year from now, I would recommend getting a used Surface. It would definitely have all the windows based functionality that someone could need. However because it just was released Friday and its price point is $499, I don't think it's a good option today. But it's worth mentioning.