If you are looking at time at home, I would watch AMR, DAL , UAL, FDX and UPS and see how the new FT/DT ruling will effect each of those staffing models.

Here at DAL you can sit reserve in base, barely work and make OK money. To make a living, you would need to work your butt off. SWA will at the current time work you the hardest but pay you the best for it. I suspect that fact will change.

If you are looking for quick career progression, DAL and AMR have significant retirements in the next ten years. (Over half of their lists) USAir does too, but they still have not merged.

Honestly, with a few years until you are faced with the decision, wait and see where each airline is at. I suspect a lot of merging etc will happen and the landscape will be totally different.