Microsoft/Bungie has a good marketing campaign right now. They are handing out a small amount of information every other day about Halo 3. They have a semi-exclusive deal with EGM at the moment, where EGM is the only (American) magazine to get Halo 3 details.
I have realized that this is probably not coincidentally timed to cover the entire release of the PS3 and Wii. With two new consoles coming out, EGM's cover story shows a Halo Spartan.
It's as though Microsoft is jingling its keys in your vision, saying "Hey! Don't look over there! Look at the 360! Shiny!" Sure, Halo 3 won't be out for at least half a year, but that's the best thing the 360 has.