BitchX, despite the fact that it has a script-kiddie following, is fairly easy to use and colorful. It's based on ircii-EPIC, which is still actively maintained. If you like BitchX's windowing system but dislike other parts of it (such as the frequent security problems and bloat), you can use EPIC, although it will be quite monochrome without a script of some sort. EPIC's powerful scripting language makes it an ideal IRC client for the advanced user, as it's very easy to customize to the user's tastes.