I recently installed Messenger Plus (http://www.msgplus.net/) to enhance my MSN Messenger experience, thinking I would simply remove it after I found it annoying. Guess not. Forget out about all the other "gimmicky" features - logging is what's critical.
Found out that MSN Messenger's logging only appears to work when you have an interactive conversation with someone. I had a friend (Chick Bornheim) message me something while I was away from my laptop. When I came back, I hit Escape and lost what he had written. Tried to pull it back with MSN Messenger's History - not there.
So instead I went to Messenger Plus's activity logs - there it was waiting for me to find it.
Goes to show how communication content has changed for so many people. My wife now regularly looks for emails from friends in England who used to write letters - I look for either new blog posts or instant messages for critical new news - going through my inbox has become so difficult that LookOut (http://www.lookoutsoft.com/Lookout/) is now my best friend. (seriously if you use Outlook, use Lookout)