I am generally very happy with my Camera and don't consider upgrading in the near future. It takes good photos and all problems so far I can mark as "User error".
THOUGH. If I was to have an extra $37,000 (yes that's right) that I don't need for anything else urgently I might just have to take a look at the new HasselbladH3DII-50
The digital sensor is roughly the size of the palm of your hand and it produces 50 Megapixel Images. (Most consumer cameras have between 8-10).
Now, Megapixel isn't everything, granted but 50 MP is quite a lot and makes this camera a good piece of hardware for the digital version of Medium Format photography.
Granted it's not the right camera for photo walks or so and it's not the strongest in all aspects as it's ISO only goes to 400 with up to 800 using Software but I still would not mind a tryout to see what images it produces thus I might have to buy some new Memory cards as the file size of each image is 65MB (almost 6 times as large as my 40D's) in RAW and 150MB saving as TIFF.