If you like wide plank pine floors, check out Wood Idea of Mercer, Maine. "I can sell you a 16-foot long, 20-inch wide piece of white pine without a speck in it," owner Michael Bartolf says from his mill office. "We're one of the only companies if not the only you can call and not be told boards like that don't exist."
Bartolf gets my vote because he can get me something I thought was gone, provide a high-quality and reasonably priced material, and has other inventory that'll help detail a job.
While Wood Idea mills T&G, ship-lap or s4s, wainscot, siding and cabinet-grade pine stock, I think the coolest cut they make is a single-piece pine countertop. Check it out: it's a 3-inch thick, 24-inch wide pine slab.
Pine Flooring Direct