Any livery that has nothing but a white fuselage with the airlines name on it is BORING to me (ie Air France, Delta (new), South African, Mexicana etc etc). Come on airlines, let's come up with something cool looking and memorable other than a boring white fuselage (or at least add a cheat line or something)! Thats not to say the tails don't look good on them

Likes:
Northwest 1990-2003 (I too miss the previous logo and hate the new livery).
Canadian Airlines International
PSA
Air Jamaica

Dislikes:
AA (sorry, I'm REALLY tired of this dated look)
UA gray color scheme (like the new)
Aeroflot
LTU (too red and angry)

Dislike white fuselage, like tail scheme:
Aloha
South African
Alaska
JetBlue

SO many more to choose from and I could go on and on, but I wont