I'm also quite partial to Schwinn's muscle bike offerings. Well-built, great lines, durable paint, just generally well thought-out machines. From the perspective of quality and worksmanship, the Schwinns were only really rivaled by Raleigh.
I recently built up an AMF Avenger 5, a bit of a departure for me. The appeal of this particular bike was the slightly longer wheelbase and especially the taller bottom bracket height which takes 6.5 inch cranks in stock form. (All of the non-shortie 'Rays take 5.5 inch cranks.) The longer cranks make for better power transfer. AMF came out with lookers, as did Huffy, but the mechanical execution isn't nearly as solid as what Schwinn put out.
Cheers, Geoff