If you want to live on the west coast go with:

SkyWest, Horizon, or Compass (but SkyWest and Horizon will have a longer sit on reserve and a longer upgrade than some of the other regionals right now. And many people have had a hard time even getting a call interview from a compass without prior 121 time).

If you want to live on the east coast go with:

Too many to list. Many are hiring and have future growth and fleet plans. Some are shrinking and their future is questionable at best. Asking a forum full of pilots which airline you should choose is like asking a room full of 3rd graders which flavor ice cream is their favorite... You are going to get a lot of different answers for different reasons. I chose my airline because I own a house and have a family and my domicile will be a relatively easy commute from home. Others choose airlines based on quick upgrade, quality of contract, pay, etc... There are a million different reasons. Figure out what you want and take your pick. It seems they are all hiring for the foreseeable future.