Tough question for me. My favourite all day smoke is Dunhill (soon will be Peterson's) Elizabethan Mixture, but as I do not quite enjoy their other blends, I'd probably stick to Cornell & Diehl to have a wider palette.
I only occasionally buy some non-C&D blend, recently being Old Dark Fired. But, it's pretty much all C&D as they have what I like at the prices I like.
I'll stick with C&D, but I could coast with my Dunhill, Seattle Pipe Club, Home and Hearth, or McClellan blends, choosing one for the year. Peter Stokkebye would be another possible choice, a nice array at moderate prices.
I was also surprised not to see this name come up more. It was a tough choice for me between GLP and Rattray's. I thought many more people would be on the GLP train on this thread.
Samuel Gawith. This would not be difficult as these days I smoke St. James flake 90% of the time, a great Virginia flake with just enough Perique. After that being a V/P smoker then JF Germain & Son, the Best Brown Flake is good. Finally, between all the McClelland’s tobacco’s you could conceivably concoct nearly anything.