Who cares? Valve is notorious for delaying their games; however at least they get the job done. Personally I would rather a polished game as opposed to something half baked like Alpha Protocol.   
However with that being said. Whenever Valve releases a title (at least since the steam platform has been mainstream) there has been compatibility issues with certain system configurations (maybe less than a quarter of all users experience this).  
 
My question is this. Would you rather a polished game that is compatible with multiple configurations upon release in April or one with additional content and the compatibility at a later date? 
 
Essentially... would you be willing to wait longer so that everything works properly from the get go, so that  no matter what system you're going  to play the game on, you get the full experience.  
 
I know I would. 

I would always wait for a better product.  Even if it is 6 months.  I got Black Ops for the PC and the problems with it made me immediately hate it.  Even with patching, it has put me off it.  People complain about delays but they will still buy the end product 90% of the time.
 
Please don't let them fuck up Deus Ex!!

It always gives me an initial sting, but I get over for the exact reasons you posted.

" Please don't let them fuck up Deus Ex!! "

I can wait. Hell, I would have been surprise if it wasn't delayed. Just get it right.

A good delayed game is always better than a game that needed to be delayed but was released on-date anyway, and I'm sure Portal 2 will be worth the wait. However, that doesn't make the delay of Portal 2 any less disappointing. I'm not going to instruct people to grab their pitchforks and torches and head for Valve HQ, but none the less, when any company says a product will be released on a certain date and doesn't deliver that's an undeniable mistake.

well, it's a good thing for things to get delayed as they work on it more. it is annoying that things get delayed. it is also valve they do this all the time.

Everything is fine as long as they don't have to bring in Gearbox to finish it.

Valve and Gearbox had a sort of developmental falling out didn't they? So that would be unlikely. Also I doubt Gearbox finished Nukem, they probably did it from scratch (save.. well the engine). It's not like it is a "hard" game to make; in the sense that it does not have an in-depth plot nor does it create an atmosphere of intense emotion when you interact with the characters.... Nukem has never been on par with the Half-Life franchise in terms of story telling.  
 
Also I do kinda agree with Gamer_152. They should learn to keep to release dates or at least some sort of scheduling. They probably knew that this delay was going to occur well ahead of the announcement. They could of at least briefed the community on where they were at, exactly, and why they needed to delay the game (probably at least six months before the announcement)...