Though I find my EOS-1DS great for landscapes and use it professionally for gallery art photography, my EOS-1D is my all around favorite for wildlife use. The combination of weak antialiasing filter, fast burst capabilities and the 1.3x tele "boost" make it possible to hand hold and get some shots which otherwise would be difficult.
Following links to a young doe who was surprised to see the big Canon 70-200 F2.8 lens "eye" poking through the brush. First her startled and inquisitive "portrait" - Hello! - then her hasty "goodby photographer" exit over the fence were captured by virtue of the 1D and a good fast Canon "L" zoom.