1. Vietnam Memorial
2. Korean War Memorial
3. Lincoln Monument
Gotta disagree with The_Mac. Vietnam Memorial may be a wall of names, but its the emotion that it evokes that makes it #1 for me. Its more the other people that are remembering friends, family and comrades, than the Wall itself. I also love the Statue!
Korean War Memorial is a rather recent addition. For those who haven't seen it, its a portrayal of a platoon on patrol, consisting of a number of sculptures spread out in a plot of grass. At night, from a distance, the lighting makes it very 'haunting'. It is surrounded by a black marble wall which has been lightly etched with scenes from Korea, almost a holographic effect.