In the keynote they introduced the Retina MacBook Pro as the Next Generation MacBook Pro.
I think it is safe to assume the old unibody design with DVD slot is on its way out.
So my guess is there will be this lineup:
MBA 11" $999
MBA 13" $1199
MBP 13" Retina $1399
MBP 15" Retina $2199
The 13" Air will become their standard 13", and for a little bit more you can bump up to the 13" Pro Retina. Of course, if the 13" Retina Pro came out in October I don't see Apple dropping the old models. Although, it is possible as it would be right after their Summer school sales, so those expecting to get a laptop with a normal HDD and lots of storage can still get it, then they drop the line in October with the new line ready for next Summer.
All that I am hoping for though is that the 13" Retina Pro has a discrete graphics card. It can be less powerful than the 15" to help keep the price and heat down, and they will probably drop one thunderbolt port and chop off some battery space.