When do spanair select the flaps - as part of the after start checks or during the taxi out? Most 737 operators now do it as part of the after starts as this gives 2 check lists / opportunities to catch the error.
Do spanair MD80 crews fly different cockpits on the fleet ie) some EFIS / some non EFIS or different variants? Is the flap gauge the same on all?
On the 737 it's level with the N1 gauges which means I tend to glance at the flap indicator as we set power as a final check they're down. I also look at the ailerons out the window as I do the full and free check and can see the slats are down too - not sure you can see wingtip on Md80 though.
Finally, we're taught to check the top of the PFD as we line up to check a V of A/T, 'eyebrows' (or PLI's) are displayed and then FD on the top right FMA.
Forgetting the flaps is one of the few single omission that will kill you. (I don't if the Spanair crew did forget or whether the flaps didn't deploy).