I used trillian back in the day because my dad wouldn't let me use aim and he was computer illiterate so i didn't have a choice. I recently had a lot of problems with aim so I decided to go back to trillian. I enjoyed being able to changes the skins and my friends sn's to their real names. But I had a lot of crashes. I'm trying out pidgin now searching for which one is better. From what I've read Pidgin is bland but is a lot cleaner code wise than trillian.
I will recommend you to download Pidgin as I myself using this multiple protocol Internet messenger and very much satisfied with it's performance. Using this application you can remain connected with multiple users through various networks. http://www.downloadpidgin.org