Windows only: Trillian 5 Beta is a very slick-looking multi-chat client, and it makes being signed into 10 networks at once seem manageable. If you're one of Trillian's many fans, you owe yourself a test drive of this new version.
Trillian's picked up a more compact and Windows-7-friendly look, along with an all-in-one menu button that will look familiar to testers of Firefox 4. Using the "paintbrush" button in Trillian's top panel, you can quickly set Trillian as a wider social media deck or as a compact, easily-hidden IM bar.
There's Foursquare support (even with check-ins), synchronised chat history across all clients and a general feeling of refinement in Trillian 5 Beta. It's a free download for Windows systems only. Found something you like or wish you could change in this release? Spill it in the comments.