Now that I've done a quick read-through of Scalia's opinion in the Heller decision, I offer some observations:
1. The Court held that the 2A protects an individual right, one not dependent upon membership in an organized militia. The right exists for otherwise lawful purposes, specifically noting that self defense is one of the bases for the right. The Court recognized the pre-existing nature of the right, as well.
2. Some restrictions of the RKBA are permissible. E.g., licensing is not forbidden by the 2A, but only when imposed in a manner that is not arbitrary or capricious. That would seem to disallow much of the discretion typically exercised by issuing officials in places like New York.
3. Outright bans of classes of arms in common use by the people are forbidden. This is a key point because it disposes of the frivolous argument that even if the 2A protects an individual right, it only protects the right to keep and bear arms of a type common in use during the 18th Century. In particular, the Court notes that handguns are in common use and overwhelmingly chosen by Americans for self defense. In dicta, the Court noted that machineguns could possibly be banned. However, it left open the argument that the reason machineguns are not in common use is because they have been so heavily regulated since 1934.
4. The Court declined to specify a standard for review in 2A-based challenges to gun control laws. For example, it will leave the matter of whether gun control laws must pass rational basis or strict scrutiny to later challenges. This wasn't unexpected.
5. The Court did not explicitly incorporate the Second Amendment against the states. However, it did cite several state cases in its decision supporting the idea that the 2A protects an individual right. This leads me to believe that the Court would be open to incorporation in a future case where a state law is challenged, e.g., Chicago's handgun ban. Again, this isn't totally unexpected, since the D.C. law which was struck down was a Federal matter, not a state law. The Court tries to craft most decisions narrowly.
More comments later as I think of them.