I had a round trip BOS↔LHR that was 747 eastbound, 777 westbound; I ended up on the upper deck of the 747, which was fascinating as an otherwise casual flyer. One especially memorable bit was landing - you're basically three stories up and suddenly the wheels are on the ground, and you're still three stories up :-)

(I'm still happy to have traded that for planes with a much higher cabin pressure-altitude - and would trade even further for business-class transatlantic non-cruise ships. But it was definitely fun to have had the experience.)