marduke's ideas are all freaken awesome! great job! i think he' summed it pretty damn well.
but would also like the ability to:
1. whisper to all friends.
2. whisper to all friends in your game.
3. whisper to a single friend/person.
4. ability to join game from buddy list.
5. ability to spectate games my buddies are in by joining through the buddy list.
6. ability to see which of my buddies are in the same game together.
7. see simple statistics of the game they are in, how they are doing, opponents, heros, score, time in game, level, etc.
9. create private chat room.
(note all chatting abilities should be seamless between the actual game and the pvp.net client)