I am a 40D lover, but I recently picked up a 60D. Partly out of boredom, partly out of curiosity. I doubted I would keep it for very long. Initial reaction was not good, as the 60D just does not have that solid feeling of the 40D. I almost sold it right away.
Fast forward a bit. I'm loving the 60D. The handling/ergonomics are fine. The only time I notice the difference is if I'm just handling the cameras and thinking about the feel. Not sure that makes sense, but in real world use the 60D is perfectly fine. Beyond that, the 60D is way better at higher ISOs than the 40D. I knew what the specs said, but actual performance has really impressed me on another level.
I also like having video functionality. Though it is not perfect, it is handy to have. AF is better on the 60D; the slower FPS has not bothered me.
So the 60D is a keeper.
Now I just can't decide if I should keep the 40D as well. I have no need for two bodies. Not getting paid by anyone, and I'm not going to lug a second DSLR around for my own purposes. I just don't want to sell it, especially considering how little they yield on the open market. Not really looking for advice - if I sell it or not who really cares? 
Just relating a good predicament I'm in because of how impressed I am with the 60D.
The good news, for a while at least, is if I sell the 40D I can always pick up another for a bargain price if I miss the old beast.
)
