Hi, you should check out prince william county too, in case that is not on your radar; in my experience they are amazingly up-to-date in their ideas about giftedness. Fairfax seems a bit rigid in the type of kids they take into their programs, though they are considered to have good resources for those who qualify. I do not have personal experience with Fairfax, just chat from other parents.

Montgomery co. in Md. is a primary 'competitor' with Fairfax county, so might be worth a look too.