If you answered "Halo 3," you're correct!
The shared sentiment around Joystiq HQ is that an island getaway is just what we need to get better acquainted with Halo 3. We're familiar with the shooting of the aliens, but aside from this most basic objective (executed with superiority, by the way), Halo 3 remains a potential funbox waiting to be busted open. The reality is, we aren't on an island, and the offerings have been piled so high since late August that Halo 3 was in and out of our 'Box as soon as the campaign was conquered and a few multiplayer matches were logged. We sampled more than we explored the intricate depths of Bungie's last Halo game-until-the-next-one. Still, even a terse study of the game was enough to validate Halo 3 as a shoo-in for one of the ten best games of 2007.
But No. 6? Halo 3 gets docked for being Halo 3, or 'Halo a third time.' Bungie delivered the charm on its first swing, so there's little need for vindication (unless you were offended by Halo 2's cliffhanger). It's unlikely though, that any developer could deliver this 'total package' without having been shackled to the material for nearly a decade. Bungie's confidence in its subject has yielded an exceptionally fine-tuned product peppered with unique, community-building features. Considering the abundance of content – and the freedom to interact with the content in different ways – Halo 3 has a lasting potential that is unparalleled by this year's other releases.
Thanks to Halo 3, "Halo Nation" is now 5 million strong and growing, a clear signal that Wikipedia needs to disambiguate its entry for "Halo effect," appending a new description separate from meanings in psychology and business: A man in a green suit becomes the 21st Century's Skywalker. That's the only Halo effect we know.