On several wildlife or zoo programs I have heard it mentioned that whist most people think chimps are really smart its actually orangutangs that are the thinkers out of the great apes (well us as well I suppose). I like the way this was put:
My girlfriend is a zookeeper, and her zoo's primate department rule of thumb about the great apes is that if you leave say, a screwdriver on a gorilla paddock, they'll pick it up, play with it a bit, see what it tastes like, and then probably drop it. The chimps will pick it up, taste it, and then use it as a weapon during a murderous blood rage against anything in the immediate area that isn't also a chimp. The orangutans will pick it up, carefully conceal it, and while nobody is looking, use it to build a multistage rocket to return to their home world.
