An Airedale terrier meets all but one of your conditions. They're active dogs and require lots of exercise.
Airedales shed very little, can handle almost any kind of climate/weather, are almost totally fearless, and are very tough dogs. Great dogs, but often a little aggressive around other animals. I've owned two males, and both were quite smart, but also very stubborn.
Beagles make good watch dogs, but are definitely NOT guard dog material. And they shed like crazy in black, brown, and white...so it shows up on everything. They're still my favorite, tho.
JL