Blood Gulch was okay, coagulation was awesome and Valhalla is my favorite. And for those of you who don't know, Valhalla was inspired by Blood Gulch.
I would like to see Sanctuary, Headlong and Beaver Creek for sure. As for Halo 3 maps, I wanna see The Pit, Guardian, and High Ground. Last Resort would be sick in Reach, except it was already remade from Zanzibar. But hey, Blood Gulch will probably get remade so why not Last Resort?