That's right, starting at 2 a.m. Pacific Standard Time, the Halo 3 Heroic map pack will be dropping it's $10.00 price tag, in anticipation of the April 15th release of the new Legendary map pack.
The three Heroic maps, Standoff, Rats Nest, and Foundry, will become required for the Team Slayer, Big Team Battle, Ranked Big Team, and Rocket Race playlists.
The new Legendary maps, including Ghost Town and Avalanche will not be forcibly integrated into any playlists, except the Legendary DLC hopper.