772 is the 777-200, which, on American, probably has the BEST coach service on the JFK-LHR route (Virgin is the only possible exception). Seat pitch is pretty good (better than any other coach I've traveled on).

However, here's the kicker: AA has in-seat power in coach on the 777 (and nearly ALL their international flights). It's not in every row, but check out SeatGuru to see which ones have it. This means you can load up movies/TV shows on your laptop and get your own in-flight entertainment, or otherwise keep yourself amused in the skies with your laptop. The last time I flew to Europe on AA, I flew coach and managed to watch an entire season of 24 on the in and outbounds (plus a few flights around the continent, where my laptop battery lasted). Good stuff.