I don't know Macdad, the best sandwich? I'd have to say it came from a Jewish deli, like
5) Art's in B.H. or Studio City
4) Mort's in Pacific Palisades
3) Shep's on Pico (I think it's gone)
2) Carnegie (N.Y.)
1) Webbie's on Laurel Cyn and Ventura (*sniff* gone...)
and was probably a hot brisket/pastrami combo with coleslaw, swiss cheese and Russian dressing on rye or onion.
Or maybe a tongue/liverwurst combo.
Non Jewish deli mentionables:
The Tam O'Shanter on Los Feliz has a GREAT sandwich board, and is a pretty good restaurant too. Owned by Lawry's, so the prime rib is terrific, too.
Here in Phoenix there are a couple of places, Luke's and Guido's, that make outstanding Italian beef/sausage combo sandwiches (ALWAYS with peppers and provalone).
My dad was born and raised in Upper Darby, Pa. I have no excuse for not getting over there one day to try real Philly cheese-steak.