Valve is scheduled to exhibit something in the "strategy" genre at Gamescom, which likely will be Dota 2. They've been so quiet about this game since the initial announcement that I cant wait to see how far along it is. 
 
http://www.gamescom.de/en/gamescom/ausstellersuche/suche/suche.php?&fw_goto=aussteller/details&&kid=0040075218&values={%22stichwort%22%253A%22valve%22%252C%22start%22%253A0}

Oh man, good find.  I'll pool in with your bet that it will likely be Dota 2 also.

Can't wait.  I'm tired of having to play Heroes of Newerth and League of Legends.

Finally, I inquired about the original DOTA's future. Does this spell the end of the classic Warcraft III mod, and is IceFrog contractually bound to stop working on it?We don't have contracts with anyone at the company. So, I'm not sure how IceFrog could be under contract Newell told me.But I think he intends to continue supporting it. The problem is that there are things he can do in DOTA 2 that he cannot do in the existing model.

It will obiviously be Half-Life 3: Tactics, Valves next forray into the Half-Life universe as a Real Time Strategy Game.

From  http://blog.dota2.com/2010/11/dota-2-qa/ :  

Q: Are you going to work on DotA after DotA 2 is released? 
A: I plan to keep DotA updated for as long as the community wants. That being said though, I think that DotA 2 represents the long term future for the game.