We had gravel in my parents house (normal 4 bed semi) - it was a magnet to all the kids in the neighbourhood (including all my friends) and my Dad spent a lot of time knocking on the window.
It need to be maintained to keep the weeds down and needs topping up from time to time. But having said that and having had cobblelock on a patio area - which also needs maintenance (cleaning and weed control)
if you aren't in an area with lots of kids I would go with gravel.