@ Maemish: Great shot, nice colors!

Actually, this is the "real" rendering of the n900 camera.
I personally end up by liking it a lot.
Then, when the pic is made into the stock app, the vignette is removed and the image is corrected to become "flat" and normalized.

I really would like to build the same correction filter. We could use it into darktable, playing with the amount to apply it more or less. I studied it a bit but it is not so simple. The vignette is affecting not only brightness but also contrast and color balance.