We did not hear anything about Halflife 2 til around 2 months ago.. lots of speculation, but nothing to build our anticipation up. Doom 3 has been announced for some time, and if it's not released this year, it could follow DNF.
Duke Nukem Forever was announced 5 years ago, and as much as I anticipated the game after watching the trailer, I have since long forgotten about it except when stupid news pops out of their mouths about it still being in development. Who cares.. release the damn thing or shut the hell up because we all heard it before and it's getting old. It's like the boy who cried wolf.. when the game comes out most people are going to say 'Really? I did not even know they were still making it."