There appears to be a problem with Address book integration. Not sure if this is a new "feature" with Leopard, but it appears that you can't combine all contacts even if they are all in your Address book under the same contact name. Only two show up.
Since upgrading to the latest version of Adium, I have had problems with my address book - I have it set so if someone on my MSN contact list is in my address book, it shows up their "real" name. This had been working from since I first started using Adium (about 2 years ago)
I had been noticing that the "real" names were not showing on my contact list last week, and clicked to add that persons details back onto their address record. This worked fine, until someone elses details had been removed.
It seems that the details for the IM address for each person is being removed from Address Book - quite annoying! Anyone else experienced this?