from what i understand, that half-life 3 thing was debunked, but everything else seems like it'll be coming out. the last time there was a leak 24/30 things were released.
on the topic of half-life 3 though, i can understand why valve hasn't released it yet. when they originally released half-life they had the intent of becoming their own online video game vendor and figured they'd grow from there. most of their releases after that were to further push their platform. they've always planned to transition from being a developer to being more of a business, so unless somehow releasing half-life 3 is gunna help them push some sort of new market on to the public, it's gunna stay under their hat. weird that it isn't being utilized for their new hardware stuff though.