Interesting, I thought I saw some news passing that he admitted he would never finish them, seems like now I can't find those back (maybe they were just ironic and not accurate).
I'm calling Half-Life 3 in the near future, maybe even a new iteration of the Orange Box. Valve has been weirdly active about their old IPs and rumors are flying.
I'm basically looking forward to it being one of the best things to come out of the US this decade. Finally, an export we can be proud of.