This post is part of our Hottest Products of 2007 feature. Also check out our other Hottest Products of 2007 posts and let us know which product you think is the greatest thing since sliced bread.

For gamers, the experience is everything, and their heroes are not the wonks designing Microsoft (NASDAQ: MSFT)'s Xbox or Nintendo's Wii, but the creators of the worlds that hold them in thrall. None has done it better than Bungie Studio's Halo 3, the first-person shooter game that is one of our Hottest Products of 2007.

The numbers demonstrate just how this game annihilated its competitors. 4.2 million units were in stores on the day the third iteration of this game was unveiled September 25. In the U.S. alone, Halo 3 grossed $170 million its first day, and $300 million in the first week. More than a million players competed live in its first day of release, via Xbox Live.

The game is set in an involving future in which the human race wars with alien invaders, the Covenant. The compelling story line, outstanding graphics, weaponry and variety of action combine to provide the most popular video game entertainment in the field's history.

It also has proved a huge advantage for Microsoft's Xbox system, the only system that runs Halo 3. With Nintendo taking another approach (also successful, but very different), the Xbox has managed to wound its only real competitor, Sony (NYSE: SNE)'s PlayStation. By following Halo 3's viewpoint character, Master Chief, in a full frontal assault on the gaming system industry, Microsoft has won the skirmish, if not the war.

If you've had some experience with this product, let us know about it. Or if you know of something else that you think is one of the Hottest Products of 2007, feel free to tell us about that as well.