One of the most popular and customizable third-party clients in the multiservice chat category for Mac continues to impress. It supports multiple services, including AIM, Yahoo, MSN, Facebook, Windows Live, and Google Chat. Part of what made the original Adium so attractive was the multitude of IM service options, and that still forms the core appeal of this client. The interface is smooth and lean, fitting in well with the Mac OS. The client supports tabbed browsing, encrypted messaging, and you can transfer files to your buddies, though it can be hit or miss depending on what service you're using.
Recent updates have improved cross-service support (both in terms of security and performance), and the app continues to offer extensive options for customization, with a wide range of sounds, themes, colors, and other tweaks--including support for Growl, if you want to keep up with chats when you're not in Adium. Under the hood, the program shares the same open-source core as multiplatform client Pidgin.
Overall, despite some file-sharing quirks, Adium X is a must-download for those looking to connect with multiple services. If you've been looking for a chat client that plays nice with other chat services, Adium is an excellent choice on the Mac.