It would be great to have "Reply to All" link in a PM so you can reply to all the people that that PM was sent to, not just the one person who sent it to you. I custom programmed it once and everyone loved it but then an upgrade wiped out my programming and i havent been up to programming it again.

The Personal message system is supposed to be revamped in 3.0 to be more topic style (facebook message like). That means it will incorportate your suggestion, as everyone would be able to see it.