Similar but slightly different, the Embraer E-Series (170/175/190/195).
I made some major missteps and came into NAC just yesterday. But the first of my ordered E-170s just arrived and I think it's going to save me by bringing in enough cash to give me some breathing room.
As far as cashflow goes, it's everything that's magical about the 737/A320 line and it allows you to get in to some smaller airports that are nonetheless quite profitable. I think my average segment length is about 650nm on it, and even when the lease payments hit it will be solidly in the green. In particular, the low fuel flow works well.
I'm also thinking about placing an order for the Mitsubishi regional jet in a year or two to handle some of the slightly longer routes.