I recently started using CenterICQ as a Jabber client, mainly because imcom has a bug in its presence reporting code (basically it never sets the user as 'online'), and it is a bit inconvenient when chatting to several contacts at once.
The interface is slightly disturbing at first, but not for long.
The biggest problem of CenterICQ is its total lack of documentation. Here I'll record the result of stuff I had to look into the _code_ to find.
Keys can be changed in ~/.centericq/keybindings
First key to change (for me) was \cx to <enter> for send_message. I see little point in multiple line messages.
Contrary to what the documentation says, not all commands are in that file. bind editor \cn next_chat to jump from one active chat window to the next one. (There is also a prev_chat command, which I have not yet mapped).
Next I'll look into remapping some more keys: I want to use j and k to move in the contact list.