If history of the airlines comes into play, and who has been able to compete and come out without too much pain, and has had a history of that, then you are looking at Skywest, ASA, and Republic. These, in the worst time for aviation, have done relatively well. Each are positioned better than most with 70-100+ seat airplanes which I'm told is the future of small jet flying. Republic is changing it's business model so no one really knows how that is going to turn out. Eagle has also weathered the storm, but who knows what AMR is about to do to them.
PNCL had a good hold on 900's and good deal with turbo props with the Q400's, but Delta actually owns all of their 900s, and there is a stipulation written into these contracts that if delta wants these jets back they can take them. (same with all the 900s that are flying Delta colors)

Good luck! Trans states just put a firm order for 50 Mitsubishi jets. Who knows what that will turn into.