EDIT: Eqo does in fact work, but has a very user-hostile interface for instant messaging, possibly as a result of being intended primarily as a VOIP application.
On the chat/message window when talking to an MSN contact, you cannot type a new message. You actually have to go to a separate "compose message" screen to type, and then send, at which point you're returned to the main chat window. Any messages that come in while you're typing are not visible, until you finish and return to the main chat window.
Fring still cannot initiate a new chat session with an MSN contact; it must be instigated by the other side.
A shiny new penny goes to the first person who can recommend a free IM app that works well with MSN...
Thanks for the ones mentioned so far... they come close and I will settle for them if necessary, just hoping there's something a teensy bit better. But then I know it's freeware and beggars can't be choosers.