According to a Google AdWords ad put up by HTC itself, the dual-core beast of a smartphone will be released on June 8th. Of course, HTC removed the ad promptly after it made the news, but screenshots like the one below live on.
The 6/8 theory is corroborated by a product shot of the Sensation which contains a weather widget citing the date as "Wed, Jun 8." Coincidence? We think not.
Needless to say, this could just be a placeholder, but we're going to keep our fingers crossed nonetheless - we want that "instant sensory overload" already!