I haven't used OS X in awhile, but IM clients should just copy Adium. It is (was?) so simple and light and easy to use, it integrated perfectly with OS X's Cont

I haven't used OS X in awhile, but IM clients should just copy Adium. It is (was?) so simple and light and easy to use, it integrated perfectly with OS X's Contacts app, and it was also being easily themed and styled by users. Also its dock icon showed the last few people who had messaged you in the background, rather than just the count of how many messages you had missed.