They seemed to have had a successful initial direct meeting ("summit" might be a little inaccurate). They share a lot of common interests: keeping Putin out of it, keeping China, Iran, and India off-balance and receptive to their separate influences, threatening North Korea, keeping natural gas prices down.
Some kind of progress on strategic arms reduction will be necessary for Obama's program to protect what's left of nuclear nonproliferation, and I think Medvedev will work with him on that. Hopefully, a clear understanding of the missile defense issue was achieved: the Russians consider it a joke but a bargaining chip of symbolic importance to them, the US is willing to give it up if success is attained in preventing Iran's development of nuclear weapons.
I doubt that the formula for Georgia and the Ukraine has been found yet, though. Including them in NATO is unacceptably close to an encirclement/containment strategy for Russia (the Baltic States don't matter), while the US will find it necessary to remain supporters of those two countries' aspirations to remain something other than just former-Soviet states.
Meanwhile, Hillary Clinton has the tough job of negotiating with India on greenhouse gases--I'm thinking some sort of biofuel project is the way out of the room. China will be easier, I think--a deal on "clean coal" development--which will be a huge benefit to the future No. 1 and 2 economies if successful.