Arkansas and Florida would be the most likely pickups in the south. If Democrats in South Carolina and Georgia can win the open Senate races in those states this year, then this would open the door to defeating those incumbent Governors. In New England every Governorship will be a potential pickup, including New Hampshire if Democrats win this state's U.S. Senate race. New York and Ohio are two likely pickups which will probably have retiring incumbents in 2006.
As you have mentioned..Minnesota and Maryland would be easy pickups. Hawaii will be another easy pickup. South Dakota and Nevada have incumbents that can be defeated, but would not be easy pickups.
<
http://www.uselectionatlas.org/GOVERNOR/menutextj.html>