Wait, this is crazy! VAlve would never delay a gam...... oh, never mind.
Heh, yea its not like Valve to ever be ashamed of delaying a game! " Yea yea september 30th 2002, you can count on it!"
I don' t think HL2 is the greatest FPS, but I do like their style very much. They do this interactive cutscene thing pretty well, with really nicely designed environments. The only thing I would change about the HL games would be to make those cutscenes more story driven than action oriented.
It' s all well and good having the player motivated to get to the citadel and defeat the totalitarian alien menace (and then get to the citadel again after having just escaped in Episode 1!), but they could reveal a lot more about who, where and what the feck is going on, in each part.
Who is the g-man, who are the aliens, what are the aliens plans apart from controlling earth, why was Breen the only one picked to be the bad guy etc etc. The game pretends to have a backstory, but never actually reveals it to us. HL2 could be a lot more than just a shooter/platformer if it did.
Now the best example of storytelling in a game would be FF7, but thats just my opinion. Combine that with what Valve do and you' re on to a winner.