What significant outcomes did the War of 1812 have on the United States?

Though no territory changed hands during the War of 1812, the war was quite significant for the United States.  The most important development from the war was a new wave of nationalism in the United States.  The United States took on the largest empire in the world and survived without any territory being lost and with its trade networks intact.  The Federalist Party ceased to exist after its members tried to take the Northeast out of the Union during the Hartford Convention.  When it became public that the Federalist Party tried to secede, they were considered disloyal Americans, and this led to the rise of the Democratic-Republican Party.  While the nation would always have political debates, they became less contentious and the period after the war was known as "The Era of Good Feelings."
In terms of diplomacy, the war brought about American superiority in the region around the Great Lakes.  Britain abandoned its forts there, and they stopped arming the Native Americans there.  Britain also agreed to stop impressment, which was the practice of taking American sailors for its own merchant marine.  The war also brought a new generation of heroes who would go on to achieve political fame, such as Andrew Jackson, William Henry Harrison, and Sam Houston.