This is a really fantastic museum with a lot of great artwork. It has a nice variety of different styles from different cultures and time periods. I personally enjoyed the art from ancient Egypt, Rome and Greece. The Roman sarcophagi were especially interesting.
What makes a visit even better is that the museum is free! They even offer free audio guides that you can use around the museum; they are available at the front desk. There is also a nice gift shop and a small cafe on the first level. I would say plan about 3 hours if you are just going to browse through the galleries you are interested in. If you want to see the whole museum you could easily spend the whole day from open to close.
When you are done, or if you want a break,check out the Washington Monument in the park across the street.







