The rugged northern coast of the island is as different from the built-up and touristy southern shore as you can imagine. You can drive along most parts of the coast but beware, the road is not paved and gets terrible (practically impassable with a normal car, check out a 4WD) in places.
All along the coast are hidden coves (called 'bocas', mouths, in Papiamento) that make for nice pictures. There are some beaches (popular with surfers) but again WATCH OUT, the current is very strong and people have drowned here.
Also on the northern coast, you will find the former natural bridge, which collapsed in 2005, the Bushiribana gold smelter, a couple of caves with Indian pictographs, dunes, the Natural Pool (difficult to get at) and Andicuri beach, with its great surf.