My own sort of related question here, Is it ok to say you want to attend a school because it's close to home? There's a few schools that the only reason I'm really applying to is because they're close to home. I'd mention more of course but that would be the main reason.
For others I'd talk about the specific opportunities they have, mission statement, etc. If you know what you're interested in maybe mention a strength the school has in that area. For example I'm interested in pediatrics so I can mention something about a school having one of the best pediatric hospitals and it would make sense as to why I'm interested.