For domestic service in the United States, I would go with United, especially if you're riding in Economy. Economy Plus for elites with 3-5" of extra leg room is great. If you're riding in premium cabins, it would depend on the route you fly most. Continental has BusinessFirst which is great on routes they have it on. United has ps service on LAX/SFO-NYC transcons. I don't fly to Europe but since I'm based in Seoul now, I fly intra-Asia and Asia-United States quite frequently. Singapore Airlines is great. They have new planes, great seats with AVOD (audio video on demand) and their service is World class. If you're flying in premium cabins, they have their new First and Business products which are amazing (SFO-ICN-SIN) and also on a few Asia-Europe flights. Personally, I think Asiana is great. Their seats are kind of old but their service more than makes up for it. I think their service is actually better than Singapore Airlines and their flight attendants are in general, quite pretty. They have new Business class products on some planes and are continuing to roll out new Business and First products on other planes.