Well mate i went the 5D becuase i wanted the Fullframe and high Iso , Excellent camera i absolutly love the camera. the prints are bigger more colour, saying that i have only L series lens.

Now if you have ef-s lens well 40d may be a good upgrade. if your not going l series lens, 40d is a great camera just not full frame.

1D be ausome though 5d does more than enough for me.