I must admit, Left 4 Dead 2 came as a rude surprise for me in E3 '09, though not for the same reasons as the Left 4 Dead boycott Steam group. I watched in anticipation for what I was expecting to be at the very least a teaser of Episode 3, only to see a trailer for a sequel to a game I didn't really incredibly care about (tempting as beating "zambies" upside the head with guitars and frying pans, I have not intention of buying this game).  
 
While it's a relief that Valve will continue to release updates for TF2 at a (semi-)regular basis now that L4D2 is finished, I do hope that Valve get's their act together and say ot themselves: "Okay, no more procrastination! Let's get Episode 3 done before people start making Duke Nukem Forever jokes about us... (again)."

Hopefully Episode 3 comes out after Left 4 Dead 2. It's been way to long.

Portal 2 > Episode 3. 

I hope Episode 3 turns out to be like another sequel if it actually does follow the 6 year time cycle that half life 2 followed.

Portal 2 is their next game.

It takes what it takes. I mean, its the climax, and Valve is very meticulous about the story, so obviously things that don't require a story (TF, L4D) will get iterations faster.

I'm hoping for Portal 2

If Portal 2 is annouced and dated before Episode 3 I wouldn't know how to feel.

L4D4

Episode 3 + Portal 2 + Half Life 3 Demo + some crazy game like Codename: Gordon or Peggle Extreme.
The Tangerine Box. Q3 2010.
You heard it here first.

I have faith in Valve. I believe Episode 3 will make it next year, and it will be epic. It isn't taking this long for no reason, I believe in Valve.
 
I mean honestly, if they push out another game (even if it's Portal 2), before Episode 3 or it has no announcements after 2010, I'm just going to consider it vaporware. I'm not crazy, right, right?

Dont know, feel as if Episode 3 will feel dated by now. Wouldn't be surprised if its a new IP.

Left 4 Dead 3

" Left 4 Dead 3 "

I believe it's Portal 2...Gabe hinted at that in some interview.

Not Episode 3.
 
It will most likely be portal 2, the casting script was leaked quite a while ago.

Probably Orange Box 2
 
which I guess would have
Episode 3, Portal 2, TF2 (with new stuff and the current DLC)

I really hope it's Episode 3 so we can all stop bitching about it and get to bitching about Half Life 3 like we should be.

I'm guessing that the next game will be Portal 2, although I'd love to see Episode 3 some time next year, I'd rather Valve take their time with it.

It's going to be Half-Life 2: Episode 3.
Why?   

http://news.bigdownload.com/2009/08/08/half-life-2-episode-3-to-include-deaf-character/  
 
They wouldn't be focus-testing for a game they did not plan to release in the near future.

Personally I think they have decided to merge Ep 3 and Portal.  There is already hints of Aperture Science in Halflife, with the success of portal it wouldnt surprise me to see it essentially worked into episode 3.  Im not sure a standalone portal game  is something id be too interested in unless they added more mechanichs, even as much as a I loved Portal.

Probably orange box 2. At least that's what I think.

I'd like it to go something like this 
Episode 3 --> Team Fortress 3 ---> portal 2

I'm not expecting to see episode 3 until at least 2011, if not even later. Ep 3 is going to be Valve's final Half Life 2 episode, and it's going to be their masterpiece, their HL2 swan song, their pièce de résistance, and they're going to spend a tonne of time developing it, making it perfect in every way.

If 2010 comes and goes and I don't have a copy of Episode 3 in my hands I shall make a face not dissimilar to this:
 

My guess, L4D3... well depends on the time table really. You gotta give L4D2 a week or so to be out before they announce L4D3 for 60 bucks. So they just might have L4D4 ready to show off by E3.
 
Though in all seriousness, I would like to see an original IP, or atleast a new engine so I can fall in love with counter strike all over again, only to prove I suck at competitive games.

" Episode 3 + Portal 2 + Half Life 3 Demo + some crazy game like Codename: Gordon or Peggle Extreme. The Tangerine Box. Q3 2010.You heard it here first. "

Surely it must be episode 3

Episode 3 will be the big E3 announcement I feel with a "long-time-no-see-omg-it's-half-life" trailer set to some epic in house made soundtrack and we'll be all happy.

I beilve that at this rate it will be L4D3 Portal 2 L4D4 TF3 L4D5 then an announcement they they are giving up on the HL series saying screw the fans, though that pretty much is what it seems like there doing to half life fans anyways

Here's hoping for Portal 2.

Orange box 2. Portal 2 in it, with Half-life 2 and episodes 1, 2 and 3. And Team Fortress 2.5 Oh what the foxtrot, add in Counter-strike. It is surprising this hasnt been put out. They should also put it out on XBLA/PSN

As torturous as it has been waiting for the next installments of Portal and Half-Life to hit and only seeing more Left 4 Dead and Team Fortress 2 (as much as I love Team Fortress 2), I hold no grudge against Valve because of it. I just hope now we have 2 Left 4 Dead games out there we'll finally get to see at least something of Half-Life 2: Episode 3 or Portal 2, I think I'd go absolutely nuts upon seeing the tiniest glimpse of either of them.

pile of crap 7 
it's video of a pile of crap and everyone will say it's amazing because valve made it

They need to put episode 3 out soon or else everyone will be expecting too much.

" They need to put episode 3 out soon or else everyone will be expecting too much. "

If it's not Episode 3 I'm going to hemorrhage blood from my anus

" They need to put episode 3 out soon or else everyone will be expecting too much. "

Indigo box: Portal 2, Episode 3 and...Ricochet 2?

I too, believe in Valve and I know they won't let us down next year... Half Life 2 Episode 3.
 
Please oh please oh please...

Seriously, we need Half Life 2: Episode 3!