At TGS Microsoft has revealed that the classic Halo map "Headlong" will be in Halo: Combat Evolved Anniversary Edition. The Halo 2 map will be remade into a new map called "Breakneck" but will also be available in it's original form.
Here is what 343 Industries has to say about Headlong.
"HEADLONG – Section 21 once looked out onto the New Mombasa Orbital Elevator with pride and optimism. Now, with much of the city eviscerated by the Covenant’s brutal assault, the skyline remains only a shattered ghost of what it once was. Headlong provides a large, skyscraper-hemmed construction site with numerous vantage points for clever snipers as well as a large central basin for excellent vehicle combat. (8 - 16 players)"