Leopard's iChat is slick and great except two super annoying things.
1) People that are away still don't show idle time. Darn it Apple, "away and idle" are really useful in knowing if your buddies are actually away, especially your friends that insist on keeping up their away messages even when they're at their computer (I've been guilty of this)
2) Why does iChat insist on having a separate buddy list window for each account (eg, AIM and GChat?) Clutter!