IN my high school, every teacher has his or her own computer and desk, all Dells. My 7 year old brother plays games on the internet in his classroom during his 'playtime' (there's restrictions)) I think the NY school board mae a deal with Dell for cheap computers, cause every classroom has 3-4 Dell computers (this is for elementary school or little kids. I would never get a Dell for my gaming needs, though public schools here are packed with them.
If they put ATI or Nvidia cards in, they would sell more.