What if the entire U.S went nuclear (I don't know how many plants are needed to make that a reality... a 1000 new ones would be a good start)? It would definitely lower energy prices across the board. How much oil would that free up for other areas?
Not much unfortunately, though we should be building nukes. Problem is nuclear is an electrical generating power source, whereas very little oil is used for electical generation- we shifted away from that in the 1970s.
We use oil for:
Motor vehicles- 9 million barrels a day
Airplanes- 1.6 million barrels a day
Distillate fuel oil- 4.1 million bbl/day
Residual fuel oil- 0.8 million bbl/d
http://www.eia.doe.gov/emeu/cabs/usa.html
That accounts for 76% of the total according the above source with the remaining 24% I suppose going into feedstocks for industrial chemicals and goods such as pesticides, fertilizers, pharmaceuticals and plastics
Now some feedstocks are obtained from natural gas and coal and suppose we might be able to shift that away from oil even further. For motor vehicles we might over time be able to shift from gasoline and diesel to a combination of biodiesel, hydrogen, batteries. As for the airlines- I think in their current form they are in deep trouble. I don't know of any way to power a plane without using oil based fuels.