Anonymous wrote:If it were me, I would plan for 7:30.
Agreed- it's an optimal time to arrive, the big wave of Europe departures go between 5-7 PM, so after 7 PM things slow down a lot. We had a 9:20 PM departure this summer, arrived at 7 PM and spent an hour in the lounge (planned to eat dinner) and got to the gate for boarding just under an hour before departure.
If stuff happens around TSA and ATC it will delay everything, so you would probably know about it in advance, or every flight will be delayed. Definitely track the inbound plane to be sure it's on time.