-Cede all of Florida West of the Apalachicola River to Alabama. It looks better on the map, the voters West of the Apalachicola probably have a lot more in common with the people of Alabama than with the people of Central and South Florida, and the move of this very conservative area would shift Florida to the left.
That's always been my personal #1 on this subject (after merging ND and SD into one state, but that's not really a slight change).
Would it be too much change to give the Texas Panhandle to Oklahoma?
Every county west of Frederick County, MD and extreme SWVA (all counties west of Blacksburg) all go to WV. West Virginia now borders TN and NC.