I guess everybody has a ladder. The cy's you don't want to work for at the bottom and the good ones at the top.
Depending on how and where you would like to live, which challenges you want to take and your family/social life, the top five will differ. The cy's stability, route structure and future plans (read career options) are a major factor too.
Depending on where you are on your personal ladder and which seniority number you have in your present cy, you will apply for another job.
In most people's top five you will probably find: Emirates, Singapore, British Airways, American and....I will leave the fifth one open.
Regards,
Twieke