I use MSN Messenger *(the new version is better) also disk9xx@msn.com. Lately, I have been using Qnext (Java). I haven't used Trillion. (I"m going to take a look at it)
I run XP Pro 2g Ram P4 3.80GHz - 260g Hard Drive Dell 8400
Shaw Hi-Speed - + everythng
I use GAIM instead of Trillian because it is free, in addition for my corporate LAN I use the Akeni LAN messenger because it does not require the internet