I live in California, so the American Eagle over Republic seems kind of funny. Usually I would switch these two in order, but this is MY top 5.

1. Skywest
2. Express Jet
3. American Eagle
4. Republic
5. Horizon

Skywest, ExpressJet, and Republic are the top regionals to be at today. Skywest and Republic are growing, while ExpressJet is experiencing a lot of attrition due to CAL hiring. All three have good pay, good work rules, and a quick upgrade.
Horizon is a quality regional. In fact, they are so high quality that people stick around for a long time. So the upgrade is near 6 years. If you live in the Pacific Northwest, or you are looking to end your career at a regional (because you are getting old or like the northwest), Horizon would be a great place to go.
American Eagle is going to have about a 3 year upgrade (t-prop) if you get hired today. The flowbacks are leaving, more flowthroughs will likely go to AA, older Eagle captains are retiring, and AA will be hiring around 2009-2010. They are a quality regional, they just have been getting a bad reputation because of the upgrade. And that is changing. So they are on my list because of the LAX base.