lots of people i know stick with their original camera. with the 60d, it's not like you'd need to upgrade - it's a very good camera. i haven't tried the nikon, but the same is probably true. heck, i know people who use rebels with L glass because they find the 30, 40, 50 or 60d too heavy and don't need the other features. so choose your camera based on what is comfortable for you to use and carry - a camera that's annoying or uncomfortable can make the photography experience a lot less enjoyable.
besides, for some of us the next step up is too heavy.
Originally Posted by whitekoda
But, why is the ergonomics so important? I ask this because if you buy into a brand, you are most likely going to upgrade the body at some point and then the upgraded body could be better or worse than the original body you liked, correct?