Favourite locos:
USA : JetBlue
Europe : Air Berlin
Legacy carrier Long Haul: No favourites because I tend to fly KLM because they're convenient and I'm an FF with them. They have cheaper C Class fares for advanced bookings and I find the service and comfort acceptable for that price.
Having said that, I always find these kind of threads very subjective. It could only be of any significance if we all flew on every carrier in the world!