Like others, I have a few #1's but if I had to downsize to one it would be the 1B in '06. It would pretty much cover the range of hunting in North America and in a pinch can be loaded w/small pills for shooting varmits. Besides that, it's fun to shoot, easy to carry, and as a reloader, with all the options available in bullets and powders, it could keep me busy experimenting. IMHO it's the all round cartridge and suits the #1 to a T.