Multiprotocol IM clients on OS X – a list I have tried so far

IM is one of the PIM applications I often rely to. I still use ICQ for that matter (and AIM, Yahoo! MSN, Skype). For anyone who needs a multiprotocol IM client on Mac OS X. I won’t go into details and what I like/dislike about these clients as it is a personal thing. Some are more developed than others. Some are more native than others. Some ore more opensource than others. And some are easier to set up than others.