Higher octane fuel does not increase power or reduce the amount of carbon buildup. The higher octane rating is related to the fuels ability to avoid predetination in higher performance or forced induction engines. If the manufacturer of your car recommends regular, running premium will offer no benefit. However if you run regular in a car recommended to run on premium you could cause issues.
http://en.wikipedia.org/wiki/Octane_rating
When I had my 04 Ram (mid grade fuel was recommended) the owners manual actually said use of premium fuel is not necessary and continued use may cause adverse affects to performance and mileage.