Gettysburg is sorta ruined for me by all the statues every few feet. Antietam (even closer than Gettysburg) looks 10 times better with 1/10th the crowds.
But Gettysburg is the anvil whereon this nation was forged. Crowds or not, tour buses or not, people who want to understand how we got to be America should go there to walk the line of Pickett's Charge, climb the rocks of Devil's Den, and look down from the heights of Little Round Top.