From what I have read, Beach/Yacht Club pool is always first.
Boardwalk is usually ranked second. For kids your sons' ages, the French Quarter pool might seem too baby-ish. AKL has a nice water slide and zero-entry pool. Poly is supposed to have a great volcano pool.
If that is the deciding factor, I would go on the Disney website and see if you can find pictures of the pools. Don't forget to check out the Swan/Dolphin Grotto pool, it's supposed to be nice, too.