3 reasons i dont primarily use trillian
1. msn 6.0.x can share audio. i use this all the time when lanning with a friend, as it sounds way better than roger wilco or some other alternatives.
2. msn 6.0.x can share webcams. thats just plain fun
3. msn 6.0.x has cool little display pictures. also fun

i do like trillian. just not as much as the new msn. i use trillian, but only to connect to the icq network.