not absolute rank, but some notables:
good:
Lufthansa . simple , clean. lovely logo
Qantas.
ANA.
JAL.
certain United config.
undecided:
TAP. colorful and whimsical.
LOT.
bad:
Vietnam. not appealing color.
Southwest. a blue suppository
Thomas Cook. boring.
Alitalia. boring.
Niki.
Air Berlin.
Korean.