Hey, I'm Grade 8 and Graduation is just around the corner and I hope to get a computer somewhere around this month. My budget would probably be 800-1400. I'm a gamer but I'd also use my computer for watching the movies, Surfing the internet and listening to Music. I'm from Canada so my currency is CAD
First... I would recommend the Cooler Master HAF 922 for your case.
Second... I would go with the AMD Phenom X4 955 over the X4 965. The X4 965 is basically an overclocked X4 955 at a higher price.
Third... I would go with Corsair, Antec or Seasonic for your power supply manufacturer.
Fourth... Don't buy into the SATA 6.0Gb/s hard drives. They still don't have enough throughput to push the throughput of a SATA II currently. I would recommend going with either the Samsung Spinpoint F3 1TB or Seagate 7200.12 1TB drives. They are pretty much the fastest SATA II drives outside of Velicoraptors.
Overall, a good build for an 8th grader... I don't want to have my daughter see this thread though. She'll expect something for her Kindergarden Graduation