Milton is really nice, as is John's Creek, but I'd be hard pressed to ever live in Fulton County. Property taxes are ridiculously high and most of it does not get returned to the north end of the county. I live in Cobb as well but, as Bar said, we're running out of land for new construction (at least in the parts of the county you would want to live in). Northern Cherokee county seems like what you're looking for.
If you can push out your drive time a little bit, Jasper, Ellijay, or Big Canoe would be worth looking at (price tag starts getting higher again around Big Canoe.