Still sort of a rumor (and this isn't the first time the date's been thrown out), but looking official: http://www.gameinformer.com/b/news/archive/2013/04/24/source-next-xbox-reveal-set-for-may-21.aspx
https://xboxevent.com/ edit: Think they just restricted access to it. But basically seemed to confirm this news. And it seems the site is definitely from MS. So we can scratch out the "rumor" part of this info I think. edit2: And if there was still some doubt: http://majornelson.com/2013/04/24/xboxreveal/
I don't really follow this guy, but I seem to recall him pushing the 5/21 date before (among other things): http://windowsitpro.com/paul-thurrotts-wininfo/here-comes-next-xbox
Can't wait. Most looking forward to clearing some of the questionable stuff regarding some rumors. I'd like to stay with Xbox since I loved my Xbox 360, but I'll be open to the PS4 also. Whichever one sells their console the best is the one I'll go with.