The best one that I have found and hangs on my wall is JNCA-5 (Jet Navigation Chart -high altitude) published by the US national Imagery and Mapping Agency. It is 1:3,000,000 scale and covers from 24 deg N to 48.5 deg n and from about 75.5 W to 127.5 W : that is ALL of the US and a good part of Canada from the Pacific but cuts off part on the north East New Brunswick and all of Nova Scotia. This is all dispalayed on one side, the other side is blank and is about 4 ft x 4 ft . Cities , topoghraphic detail and enough aeronautical info is displayed making this my first choice for VFR trans continental flight planning as well as great looking wall chart that doesn't need to be pasted together.
Bought it at Oshkosh for 5 bucks but I can't remember from who. Love to have another for the hangar. If you locate a supplier pls post the info.
Ben