I can understand why it's taking them so long - they're building a new game engine from the ground up after all. If they perfect it then we'll probably see a slew of games using the licensed engine, which could be fun.
As far as the actual game goes, I'm not all that excited about it. ID haven't been on the ball in terms of gameplay in the last few years in my opinion. Doom 3 was a letdown compared to the original Doom and Doom 2 - they changed the gameplay too much although I've heard that Doom 4 will be more like the originals.
The game I'm waiting for some news about the most is Half Life 2: Episode 3 or even Half Life 3.