My initial reaction to the news that there was a 4th edition of the Dungeons & Dragons game coming out was: Feh. I'm already running a version 3.0 game, and there's no way I'm shelling out a big wad of money for new rulebooks that will totally change the system and end my current campaign.
But I keep hearing good things about it (http://blog.wired.com/underwire/2008/06/dungeons-dragon.html). Admittedly, much of what I'm hearing might be coming from industry shills. But still, it's interesting and I want to hear more.
I will not end my current campaign or make any changes any time soon, but maybe when we get to an end of this massive story arc that is slowly playing out, I'll switch over. That would be years from now.
Still, it's a pity that they didn't come out with these great improvements for the 3.0 release in 2000.