Reviewers use all sorts of convoluted criteria to determine which airline is "best," but for me their reviews are mostly irrelevant. No reputable airline's planes crash much more often than another's; the planes all come from the same handful of manufacturers anyway. Similarly, the food all comes from The Chicken Or The Beef Catering Corporation. And most airlines give a "free" trip for every five or so you take.
For me, the choice of airlines is determined by whether the flight attendants are generous enough with alcoholic beverages to keep me suitably stupefied during stupefyingly long flights across an ocean. Most airlines have concluded that free drinks are a good investment: inebriated passengers are generally passive cattle.
I've only found one exception: KLM Royal Dutch Airlines. Their stern ruddy flight attendant reacted to my request for a second beer as if I was raiding her queen's private reserves. Scratch KLM. Curiously, their business partner, Northwest Airlines, is one of the most generous. On one flight I left with 20 little bottles of Scotch--a full liter. I'm taking it easy this flight, though; nine bottles is just enough to face Michigan.