Portal 2 8 vs 8 competitive multiplayer that rivals COD
Duke Nukem Forever 2
The Orange Box Squared with Counter Strike 2, Half Life 3, L4D 3, and Portal 0.

A point and click adventure featuring Gordan Freeman
A new IP that involves an anthropomorphic pineapple as the main protagonist

Episode 3 actually coming out
new Counterstrike
 
and a completely new ip!
 
....
 
Just kidding probably a TF2 patch

Left4dead 3

New Left4Dead,new IP and Half-Life ep.3. Cant see a new Counte-Strike happening as they are running a constantly updated beta for people who bought Source.

• HL2:E3 (PLEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEAAAAAAAAAASSSSSSSSSSSSSSSSSSEEEEEEEEEEEEEEEEEEEE MOTHER FUCKERRRRRSSSSSSS!!!!!!!!)
• Errrmmmm. HL2:E3
• Yeah. HL2:E3.
  

L4D3 
L4D4 
L4D5 
 
Confirmed! ;)

• Team Fortress 2 Update, Sandvich new Class
• Left 3 Dead 4
• Episode 3 cancelled because of lack of interest

Valve bought by Whiskey Media and renamed Vealve, Whiskey's new food site, featuring Will and Norm bacon cook-off.
Episode 3 is now a hunting game, and you will be able to carry over your acquired meat into the singleplayer of Portal 2, now called Cooking with Portals.
Atleast that's what I hope for.

" L4D3 L4D4 L4D5  Confirmed! ;) "

I'd love a new TF2 patch.
 
But it's probably something boring like HL2: Episode 3...

Steam Stream? A streaming games service for steam.  Possibly a subscription service, possibly used for delivering demos. 
 Episode 3 has got to be one of them. 
I'm guessing some new IP too although god knows what that'll be. It won't be out this year anyhow. 
 
I'm also hoping for more killer TF2 patches but I can see that dying down :'(

Half Life MMO

HalfLife movie

L 3D 
 
3 surprises... in 3D! 
 
3 Survivors, 3 new special infected, new 3 vs 3 survivor deathmatch! All this in glorious 1080p 3D! 
 
(Computer capable of running 1080 3D and monitor not included)

SHOGO!
 
Episode 3
 
 
SIN!

Half Life 2 Episode 3 
Half Life 3 (Heavily modified source engine) 
Counter Strike and Day of Defeat on the new engine.

Dota is the obvious one 
Team fortress 3? 
episode 3? 
new IPs?

Within the next year:
A new Source engine will be released. It will be fully DX11 compliant, with full quad core support. Crysis will look like shit compared to this.
Half-Life 2: Episode 3 will be released...
...and it will be open world with more than 50 hours of gameplay just for the main story alone. Yes, there will be sidequests.
 
Also, due to some terrible mistake, I will be crowned the king of Europe. Fuck yeah.
 
I'm honestly not expecting much. Maybe some DoTA announcement. Maybe they finally got through the red tape at MS (yeah right), and TF2 will be fully updated for the 360. Also, Gabe's girth will make him implode, causing a small black hole that will consume the entire solar system.

Well one of the surprises has to be episode 3 because continuing to ignore it's existence would be the expected thing to do.