My pic would have to be the 1978 Raleigh Super Course, its the first year for forged dropouts and although only a three tube 531 frame, its robust enough for daily use and general purpose riding. The same year Super Grand Prix is a close second, which came with a step down in derailleurs with the VX vs the Cyclone on the SC. Weight on the two models is very similar, likely only a few ouces difference between the two.
I owned both, I sold the SC and kept my SGP. I do still own a 1977 SC, which I also bought new, but its a little worse for wear these days sitting in the garage waiting for me to get the time to restore it.