Well, if I was going to go to FF for landscapes, a D800 and Zeiss 21mm would be a very nice buy.
But I just love my 7D too much, until there's a replacement for that I wouldn't consider nikon.
And i'm just too lazy to run a dual-brand kit, like birds off 7D, landscapes off D800, and having to deal with 2 different softwares and workflows etc.

Anyway, what's the ship date of the D800? I'm very interested to see how the images turn out...