Spiker - a new Brute weapon
Spartan laser - a laser that tears vehicles apart
Nail Grenade - sticks into walls and sends nails everywhere
The Mongoose is in! This is the ATV that was cut from Halo 2. It seats two and has no weapons. Designed from recon and quick travel.
The "Man Cannon" - Spartans do their best Human Bullet impersonations for some extremely rapid transport. Players can still shoot in the air, and can be shot down.
The X button has a new, still secret feature. Reloading has now been allocated to the bumper buttons. Right bumper reloads the right weapon, and the left bumper reloads the left. Genius.
You can now see your secondary weapon when it's not in use. In other words, it's actually slung over your shoulder instead of magically appearing out of thin air. Also, a 4 DVD "Legendary" edition is planned that will have material from Red Vs. Blue, documentaries, and a collection of all cut scenes from the game (possibly the whole series?).
Additionally, 1up, one of the other organizations to have the honour to be invited for a massive press day at Bungie's Studios, has officially come out to confirm this information to be correct, and has also hinted at the ability to save video's of yourself playing, machinima style, but this was in the form of a rhetorical question so it's anyone's guess at this point.
Another awesome product of this Halo 3 news bombardment was this, it has become my new homepage, you want to know what it is i hear you say, well, it is a mini site exclusive to 1up, dubbed '3 weeks of Halo 3', the site will be updated with a series of articles, ranging from 'multiplayer map analysis' to 'halo 3 single player'. If you check out the link it will show when these articles will be hitting. God damn, roll on this months EGM already...
For All Your 360 News Check Out: 360insight
PS. Sorry if i beat you to this Jay!