I usually fly the other way - Europe to USA and my favourite choice is US Airways as they have the best in-flight entertainment in Economy, but only in the Airbus A330. Also a good choice: Iceland Air. They always fly via Reykjavik which splits the flight right in the middle. So after about four hours you can get off the aircraft, use a regular bathroom, have a snack, do some shopping and then go on. Additionally they are very inexpensive.