We always end up at Pecos Bills - we really love it there. We are planning on trying Columbia Harbour House this trip as well. I've read LOTS of great reviews on that one. We've never tried Cosmic Rays. Casey's is good if you want a hot dog. I also want to try Pinocchio's Village Haus - they recently changed the menu there.
I think you are thinking of El Pirata Y el Perico. This resteraunt you enter from Adventureland and is across from Pirates of the Carribean. It offers tacos.
Pecos Bill's offers burgers, sandwiches, wraps, etc.
Pecos Bill served us well one night when we were starving and waiting for Spectro to start. We hated Columbia Harbour House, except for the pleasant, quiet view from the upstairs.