There are things I like about a lot of airlines.
All economy:
International
Berlin air: Gives you a lovely little sleepy kit with eye covers, ear plugs, blanket, pillow, breathmints. It's so simple but awesome.
Swiss Air: greatest food service/drink service I have ever had on a plane. Made me feel like I was in first class. Unlimited alcohol, full meals/ 2 of them. A snack in which one was a super tastey sundae. I was in heaven.
Iceland Air: super cheap, no food service but you can have up to a week long stay over in iceland free of charge. Super cool perk.
Domestic:
Alaska airlines: gives you a free alcoholic beverage and constantly have perks for their frequent flyers.
Southwest: stupid cheap and you can bring your skis on free of charge.
Jet Blue: also super cheap but I've never been on a flight without a screen in front of me and i was even on one with free internet.