JetBlue. Free good WiFi, better seats with better storage, onboard snack bar, and better terminals on both ends in JFK and LAX. Small bonus points for JetBlue giving out eye masks and ear plugs on a red-eyes, having drinkable coffee, and refreshing towels on landing.
If you plan on buying meals on board, considering having the JetBlue card as the 50% in-flight discount is a nice perk.