Dana is a simple, skinnalbe IRC client. It's actually been around for a fair amount of time, but not many have heard of it. Special thanks to craeonics from teknidermy for pointing it out.
There isn't too much to say about Dana. It's a basic IRC client. It just connects and works. No file transfer or anything fancy. Between that, and ~300k file size, it's blazing fast. It does let you store a number of servers, and even has a favorites list. It also connects to you favorite channel on launch, and the icon blinks if there is not connection. Naturally, it keeps a log file. Simple features, but everything you need.
The skinning format is pretty simple and straight forward. One odd thing is that the images have to be in a folder with a .dcs extension. Another odd thing is that the site lists skins in a single .dcs file. They aren't renamed zip files (I tried). They might be another archive type, but it's hard to say with that part of the site being only in German (despite a link that claims to be in English).
If you want something simple and skinnable, this may be perfect for you. Those used to more robust clients will find it lacking in many features. If those kinds of apps are too much for you, then you many have found yourself an IRC client. It won't steal away any mIRC users, but it is fun to play with.