Blizzard has made an official announcement of Starcraft 2’s release date: July 27, 2010. Check the post on our SC2 sister site to read the full press releases and see comments from many happy SC fans.
It’s surprising to get a release date this far in advance for a Blizzard product; they must be certain they can hit this date, and they surely need the time to scale up for a massive worldwide simultaneous release. The SC2 beta is still going full speed, with the map-making tools recently released for the testers to dig into. There’s no word when the beta might end, but most Blizzard betas run nearly until the release date. (And there’s usually a huge balancing patch with all the last beta test fixes released a month or so after the game’s release.)
As for a Diablo 3 angle on this… it’s hard to know how much we can infer. A beta test for an RTS is very different from a beta for an RPG. Just on general time, the SC2 beta began in mid-February. Assuming it runs until at least mid-July, that’s five months; longe than lots of betas, but not exceptionally lengthy. If Diablo 3 is released 5.5 months after its beta begins, I think most of us would be satisfied. Also recall that the SC2 beta was set to start last year, but was delayed since the B.net 2.0 revision wasn’t yet ready for prime time. That shouldn’t be a factor for Diablo 3.
Lastly, note that July 27th is a Tuesday. Why Tuesday? Good question. At any rate, you might want to factor that intothe Diablo 3 release date.