A friend highly recommended we visit the Museum while in DC. I too now recommend it.
I brought my two kids, 12 and 15 and we spent several hours visiting the many exhibits. I personally found the Berlin Wall exhibit very moving as I had visited Berlin when I myself was a teen and it was before the wall had been taken down. My mother had also fled Eastern Germany before finally immigrating to the US. Hard to believe that it really was not that long ago.
My son really enjoyed the FBI exhibit area. I too found it fascinating as I remember several of those high profile cases.
Also very moving was the 9/11 exhibit. The pictures and video recounting that day in our history were amazing.
We did eat in the cafeteria on the bottom floor and found the food to be quite good. They had a salad bar with a nice variety of offerings.