I have high hopes for something at least hinting towards HL3/EP3 at this years E3.. I know Gabe Newell said himself that they are not talking about anything that hasn't been already announced, but.. Ask yourself this.. Hasn't Half-Life 2: Episode 3 already been announced?
We are going to be showing stuff everyone already knows about
Hmmm..
And in this same e-mail from Gabe, this list "(CS:Go, Dota 2, 10' UI,
...)" has "..." at the end.
Three dots normally implies there is something more.
Hmmmm..
Could be that new IP though. The SOB or w/e it's called with the space ships and aliens. But who knows with Valve... Portal 2 genuinely surprised me that it came out before Half-Life 3.