The ground should indeed be green in the 'pre-order release'...
I also remember seeing all the models being just plain grey instead of textured (not the ground tho'), it happened in one of the betas when I alt-tabbed out and back into the game, but I think it's fixed now...
I assume you do have a nice video card with the newest OpenGL-supporting drivers?
I'm looking at the ground, and it's completely grey. I was just wondering if this is caused by the pre-released version and will be fixed, or if it's supposed to be green and there's some other problem.
In fact, now that I look at it, only the water and the deck are textured, everything else is a solid color (including ships, trains, and cars).