Hi,
I am currently doing a wallpaper in Inkscape, and I have noticed a strange thing about gradients : we can see the steps.
Some other guys have also noticed this problem : http://inkscape-forum.andreas-s.net/topic/109624 (may 2007)
The rendering is exactly the same in inkscape, png export and Firefox (and Chromium). I have tested in Safari (Mac), and it is fine (not 100% sure : fast test).
Creating the same gradient with GIMP is fine : playing with brightness and contrast helps (contrast to ~110 and adjust brightness). See this picture : http://xinfe.free.fr/gradient.png
After further investigation, I found out that when disabling the 'Dither' option, GIMP's result is exactly the same as Inkscape. So, is it possible to implement this feature for *.png exports (opt-in/out) ? Nice article : http://en.wikipedia.org/wiki/Dither#Digital_photography_and_image_processing
I know that it's nearly nothing, but I noticed it in my wallpaper, and it's annoying me, now...
Nevertheless, Inkscape is great !
Bye