We use Yahoo Instant Messenger as the company standard. I do not like the YIM client because too much real estate is spent on commercials and useless buttons. To consolidate various clients, I had switched to Pidgin. I still run Google Talk and Skype because unifying instant messenger clients do not handle voice and video well. Here's a couple of reasons why I liked Pidgin and have become a big fan of Trillian.
- Both clients support various instant messenger protocols: Yahoo, AOL, Microsoft, Jabber (although Trillian requires you to buy the pro version).
- Tab windows. At any moment, I have multiple chat sessions open. I do not like to have four or five windows on my desktop. (For the same reasons Firefox tab browsing is key feature of a browser.)
- Both clients support various skins. Trillian is a windows application and looks a little smoother. I use the minimal GuiStyle Skin.
- Although Pidgin supports also IRC, I never installed the plugin. Trillian IRC support is great. I have several IRC channels running from the rhel, linuxnewbies IRC channels to the Netbeans IRC. The good old protocol (anno 1988) is the perfect group chat protocol. I don't know why we don't use it internally. (It could replace many quickly evolving email threads.)
- Support from Google Desktop to index my chat logs.
UPDATE: 04/02/2008 - LifeHacker Five Best Instant Messengers has high praise for Digsby