Adium came up both in an online search and from Leo Laporte when I was searching for an IM client for my new Mac Book Pro. It has a funny duck as its icon and looks like it has many more powerful features than MSN Messenger. I'm trying to stay away from MS products if I can on this machine as an experiment. Pages and the other programs in iWork should mean I don't need MS Office - time will tell.
And, so far Leopard doesn't seem daunting - that was also part of buying a new machine rather than trying to install it over the existing OS on a 3-year-old machine. I still rely primarily on my Toshiba Tablet, especially for work projects and transferring documents to other places. That's mainly because there are still translation character and formatting issues unless you use PDF - which isn't always the best option for everyone involved. And I hope to play with Pages and Keynote for my classes this semester. Should be fun.