OK so you have your favourite IM service that you like to use, but its a free world and some people are just wrong and chose MSN instead. Or you have an ID for years on ICQ that some people still use. What do you do with them all?
When you have IM ID congestion you need Adium X. Adium is a multi-protocol messaging client that is slicker than an eel skin codpiece and full of open source goodness. There are funky themes and other extras with Adium, allowing you to customise it more than and a 1987 Vauxhall Nova. Its just a shame about the Orville the Duck icon they use to represent the application, instead here is some graffiti I photographed down by the Truman Brewery a while ago..