He said the partition would be based on the line of 1949-67. Many of us recognize that this may not be historically, legally or morally the case, but practically, it is. Like it or not, that's the line the negotiations have been focusing on for years, and as the man said, there will be adaptation of it, but it does serve as the base of the negotiations.
His direct contradiction of Netanyahu's position of let's wait and wait some more, will trouble Netanyahu and his fans, but is actually plausible. We should hurry up, because there's nothing to be gained by waiting. Or is there anything to be gained by being passive while the world around us is active.
Most significant of all in my mind was that Obama did not repeat the universally silly line about how peace can be achieved anytime soon. On the contrary, he resoundingly forgot to mention Jerusalem, except to say that it will need to be talked about some other time, as will the Right of Return. In effect, his speech adopted the position of Avigdor Lieberman (and most Israelis) about moving towards a partial resolution of the conflict rather than a final resolution.
Update: It occurs to me he also seemed to say the Palestinians have some explaining to do about their new unity government with Hamas. Tick that box, too.