Quassel IRC is a modern, cross-platform, distributed IRC client, meaning that one or more clients can attach to and detach from a central core, much like the popular combination of screen and a text-based IRC client, but graphical. In addition to this unique feature, it aims to be a comfortable chatting program.
dxirc is a easy-to-use yet capable cross-platform IRC client. Among its notable features are flexible configuration, a fully customizable look independent of system-wide settings, multiple server support with optional automated joining of selected channels, and the ability to connect via SSL.
JBuddy Messenger is an instant messaging client designed for everyday business use. It supports public instant messaging networks including AIM, ICQ, MSN, and Yahoo. With a paid license, JBuddy Messenger adds support for Google Talk, IBM Lotus Sametime, XMPP/Jabber, Microsoft Office Communications Server (OCS 2007) and Live Communications Server (LCS 2005), and the JBuddy Message Server. JBuddy Messenger offers the concept of a Meta-Buddy (Trillian calls them Meta Contacts), which is an aggregation of the presence of multiple screen names under one buddy. Also, buddy groups of the same name across multiple accounts can be visually merged to simplify large buddy lists.