I recently read somewhere Valve was working on it at the same time they work on L4D.    

Either end of 2010 or beginning of 2011.

Not before Duke Nukem Forever, that's for sure.

2010 - 2011 maybe. 
you never know, i still have to finish HL2 with Ep 1 and 2. (i have the orange box, but never got around to finishing HL2, am i a bad person?) 

At this point I don't really care. There's so many other things we know are coming out that I could take it or leave it.

NEVER.

When they feel like it, that's when. 
 
*Goes back to play L4D*

yes you are. but if you redeem yourself, our lord Gordon will forgive you.     "

When it's done... *shiver*

2011 at the earliest, but it could be 2012 or maybe even later. Episode 3 is going to be the final episode of Half Life 2, and it's going to be their swan song, their pièce de résistance, it's going to be a masterpiece and they're going to take a long, long time perfecting it.

2013 exclusively for Wii HD.

2011, if we are lucky.

Half-Life is overrated I think. I don't see the big appeal, oh well. I said 2011.

I'm really hoping for 2010, but I'm very doubtful it'll even come out in 2011.

I think they'll pull an L4D2 and announce it at E3 and then put it out in the holidays.

I've been playing Half-Life again and I really cannot wait for Episode 3. 
 
I'm hoping it will be released or at least announced around Q3, but it probably wont be out until 2011.

Late 2010 or early 2011. It's the single most wanted game ever for me, especialy after just finishing my HL2 marathon the other day in which I played HL2, E1 and E2 over the week. I can't wait to explore the Borialis and finish the fight with the combine and hopefully have a long discussion with the GMan.

" Half-Life is overrated I think. I don't see the big appeal, oh well. I said 2011. "

i could see episode 3 coming out around 2014 maybe 2013.

Pretty sure they already said not until sometime in 2011. At this point Im not even expecting it then.

THE FUTURE WOoOoOOoOOOooo.
2010, either Q2 or Q3.

I'm saying 2010. Sometime in 2010.

I am really really hoping that valve will MENTION the game after the release of L4D 2.

No earlier than 2011.  Has the game even been officially announced yet?

Whenever Valve would learn the meaning of the concept of Episodic Content.  

Sometime in the middle of 2010.

Why was 2010 Q4 not an option in the poll?  Oh well, that's when I reckon it'll come out.  They've definitely been working on it in the meantime given the quotes to come out Valve in that time and the merest details of what has ben teased leaves me super-excited as to what new technology and gameplay might be introduced.  I'm hoping that they start teasing it's release early in 2010 but maybe they'll just wait till E3 to announce it and start showing it off.

2011-2013

tomorrow 

It took them six years to make Half-Life 2, and one and-a-half(ish) years to make each of the current episodes.  I can easily see it being out by Q3/4 2010.  That's still three years to make it.  2011 at the very latest.  Not that I want them to rush it.  I'm just being realistic.

I reckon they're making a completely new, overhauled Source engine for Episode 3. They can just as easily call it Half Life 3, why tie it to the old engine's legacy? Or they're going to release episode 3 using the current engine in Q3 or Q4 2010, and subsequently announce a new engined Half Life 3 for 2011.

Some time during the summer I hope, I swear to god I'm gonna punt something hard if I  have to wait another year.

For those saying never... Seriously? Valve never canceled a game before and we all know they take FOREVER to release a game but it's always very well worth it. Don't say "Well, L4D2 came out a year after the first!", technically that wasn't Valve that developed it. It was made by the Turtle Rock Studios developers but they were just bought out by Valve and made into their own division/team separate from the Half-Life series and most other Valve games.

I'm really not sure. I think the period I'm expecting it most for is late 2010-early 2011 but that might be partly out of blind hope for it to come out as soon as possible. I think there's a chance we could be seeing it as late as the end of 2012.

I'm just waiting to see what Valve decides to do after they are done with this whole episode stuff. It's really sad they had to chose 'episodes' as the name of them, as that implies a faster dev cycle for smaller content. Instead we get the same amount dev time for even smaller amounts of content. As much as I liked HL2 and the first episodes, they are NOT worth the time spent on them for me. I played through them and haven't looked back since.

I still stick with my belief that they've scrapped the "Episodic" part and are working on a full-fledged Half-Life 3 under an all new engine (which is probably more of a highly evolved version of Source, much more so than their recent releases). It will probably be announced this coming E3, with a release sometime in 2011.

I expect 2010 Q4, unless Valve have something else up their sleeve they have managed to keep quiet.

I expect mid 2010.  Something might be said during 2010's E3.
 
Also, Gabe is coding as we speak- 

NEVER!

I am way past actively waiting for this game.

E.  It's going the way of Duke Nuke'em Forever.

Pretty much around Oct 2010.  It'll have a new renderer.
 
@zicdab -  In what way?  btw DNF is still going to get released, it's just a matter of case settlement before they can proceed.

" btw DNF is still going to get released, it's just a matter of case settlement before they can proceed. "

Look, there's no need to derail this thread but I strongly believe that Duke Nukem Forever has already been completed, save for a few touch up effects (such a particle systems and canned animations) which are often changed during a game's production lifecycle.  Here;s why I believe it will be released:-
 
If the game had never been in a workable state Take Two would never have sued Apogee in the first place, because all they really want is the game itself so they they can turn their development investment and licensing costs into earnings. Their case is literally aimed at the wrong company as they made an agreement with Infogrames (AKA Atari these days) who originally owned publishing rights of the title to tune of 12million USD, none of which Apogee ever saw,   Yes they may have indeed funded some of the development cost but they have yet to prove to what degree. When this case was showing to be unjust, they further harassed Apogee to try and grab at the game assets, which also failed.  Apogee would not have bothered defending themselves to such an extent if those assets weren't directly tied to a finished product and the judge would not have allowed those assets to stay in Apogee's hands if the game hadn't shown at least some semblance of completion - inasmuch as the case was raised by Take Two as a breach of contract - likely pertaining to specific clauses of targets not being met.  Meanwhile Take Two's own devs 2k Games already started another product using the Duke Nukem license (which by the way is all Take Two own, not the 3DR assets of DNF nor the rights to the final product as has already been proven) - that game's development has been halted.  Why?  Simply because DNF is already ahead of it and this is also why Take Two wanted DNF's assets.  They know that 2k wouldn't have been able to spin up another DN licensed product to match DNF so they halted progress and hoped to steal 3DR's thunder via a court injuction which, as I already said, failed. 3DR's staff layoffs are a measure to protect those assets and to enable the 3DR devved DNF product to see the light of day eventually.  Take Two know this and eventually the case will be settled - because all either party wants is for the game to be released.  
 
Whatever your opinion is based whatever information you've gleaned from whatever sparse sources have been feeding the loop, the fact of the matter is that any game is only as good as it plays.  Prey, another 3DR game which had a really long development history and multiple reboots, was a hit commercially and critically when it finally got released.  I think DNF will follow suit.