His efforts, the hard won results those efforts produced, and the inspiration they give to millions today are what I feel are best to remember about King.
Another thing that I think is important to remember is that for his actions, King was ultimately assassinated. This happened in Memphis, TN on April 4, 1968. Someone or some group of people did not like that King was rallying the poor, the working class and the minorities of the United States into an organzised resistance against inequality, injustice, poverty and war...even if he championed a peacful protest model.
My wife and I visitied Memphis a few years ago, and among other things, we visited the site where King was killed. Today, that motel is now a Smithsonian civil rights museum. The combinatio of the somber site of King's murder with the soaring monument to what his and others' efforsts produced for civil rights made for a very compelling experience.
Below are two pictures I took while we were there. The first one shows the hotel as it was when King was killed by a gunman shooting from a building across the street. He was shot just outside his room on the balcony just behind where the white wreath not hangs. The lower pictures is the original sign for the Loraine Hotel.