Kadu now supports avatars on contacts list and chat window with Adium styles (now only for GaduGadu accounts). Implementation was done by me, Juzef and White Eagle (team work ;) ). Thanks to Qt model-view framework and to Kadu protocols' service framework this was very easy to do. Now we only need to optimize it a bit (don't ask server every time for avatar data) and to use original aspect-ratio of images.
Below is screenshot with contacts from my list that have avatars and two contacts without one, so you can see the temporary default-avatar image too.
And the chat window:
Next feature that will be implemented by me is choosed by community on our forum - support for "Show messages from today/last day/last week" in chat window (similar to what is in Skype 4).