As you may remember from his photos of Kazakhstan last year, available here, and at his blog (see my links page), he has a Nikon D200. Now while this is the daddy of cameras, if you are just looking for something that is easy to lug around all day, perhaps a little spontaneity, then the Nikon D40 may also interest you. The lens included with the body is pretty versatile, and the customizable menu system means you can get rid of the options you don’t need, and focus (sorry, bad pun) on the settings that are important to you.
Anyway, I think my favourite shot of John’s from Summer 2006 was the night time shot of the Batarek tower, it truly was stunning.