I heart Six Flags. There's one (Six Flags Great Adventure) less than an hour from me, and if I'm lucky I can get a season pass for $40. And when you walk into the park with nothing but a season pass and your car key, you really don't end up spending much money. I haven't been many other places but it has awesome roller coasters - Kingda Ka, Nitro, El Toro, Medusa, Superman, Batman, and a few others.