Margo - my copy of Leopard is on its way. Should be getting it later this week - yes, I'm preparing for the 1.5 hour install. The new updated iChat by itself is worth the upgrade for me - I plan to do tech support on my mother's iMac using it. :)
I wouldn't worry about waiting for a service pack for Leopard - Apple is NOT Microsoft by a long shot.
Masaki