Elite status is very much worth it.

Why?

1. The announced benefits of elite status - more miles, more upgrade chances and perks such as boarding privileges and the ability to use the first class counters regardless of the class of ticket you have. This, alone, is worth it.

2. Better access - all airlines give elites, at some tier - a different phone line and a different address to send complaints or requests to. Every time you talk to an airline, it is likely the agent will be checking your status with them.

3. Comping - being an elite with an airline will often mean easy elite status with a hotel chain as well.

- - -

Delta has crashed its FF program - assuming, it seems, that people who fly with Delta have no choice, and hence they don't need to give them much in the way of goodies. Hence, people with a choice don't fly Delta.

The easiest program to qualify for is AA. For Domestic upgrades CO is a better choice, but their international upgrade policy is widely regarded as the worst. Remember that AA is part of One World and CO is in the Wings alliance with KL, NW, HP and now Midway airlines - so look at which partners you might use, and what degree they comp you to.

Your other choice is US Airways, which probably means eventually being with United. United is part of the Star alliance, and thus the largest and most extensive FF program in the world. It is also a pretty stingy airline with benefits until you hit the top tier, and has had a number of problems with managing its business. However, for many people, United is the friendly skies, because it serves more destinations with more flights.