What are you going to be doing with it? What programs are you wanting to run? Do you need portability? Personally, if I was in HS still (and not having a 25th reunion this summer!) I would get a low end iMac an an iPad.
The iMac to do more processor intensive stuff like videos, pics, projects and papers.
Then I would use the iPad for surfing, facebook, email, etc.
To buy both would be the about same price as the MBP