The Black Diamond Grappling Hook is great hook that is probably the one on my rack most often used. It has great stability and works on a big range of edges from big to small.
It is probably the first hook I would buy. Second I would get the Black Diamond Talon and finally the Black Diamond Cliffhanger. That three-hook combo is really all you need to get up 99 percent of wall routes. Bring one set for easy aid routes, two sets for hard aid and maybe some other specialty hooks for really hard aid.