This is an unofficial open-source GPL X-Chat (UNIX IRC client) build for Windows, compiled on Windows XP SP2 with Microsoft Visual Studio .NET 2003 Enterprise Architect C/C++ compiler.
X-Chat has two good features of usability: colored nicknames and alignment by text as opposed to alignment by nicks. When you read text, it's enough for eyes to notice the colors of nicknames, which they can do when they are focused to somewhere else near, and you may know at once who is writing. Colors are inobtrusive and there just 6 of them--not to burden your short-term memory. And eyes don't have to search for ends of nicknames, they can start reading text at once when text is aligned by the beginning.