The opinion is strongly worded in demolishing a number of long-held arguments against gun ownership. It calls the argument that it only applies to arms that existed at the adoption of the Amendment "frivolous", and at one point says Justice Stevens' dissent is "dead wrong".
We're in for more lawsuits: the Court did not explicitly state that the Second Amendment was binding on the states through the Fourteenth Amendment (though they did hint as much), and they did not define any test to be used to determine whether a regulation on firearms ownership and use is permissible (though they did explicitly rule out a "balancing of interests" test). Even so, the Court's opinion today is about as clear as it can get in upholding the meaning of the Second Amendment as I, and others, have been arguing it for years: it protects an individual's right to own and use firearms, including handguns, for self-defense as well as hunting and defense of the country.