Stout Strength/Analysis
There's a reason why most weightlifters in the Olympics don't look as polished as the bodybuilders you see in magazines. The latter don't merely have to build their muscles; they also have to keep fat from hiding them in order to achieve that chiseled look. However, strength is determined by the muscles themselves, not whether there is fat as well; losing it is mostly a matter of showmanship for bodybuilders. Not to mention that a one hundred pound weight suddenly seems like a lot less when you've been walking around with five hundred pounds of blubber attached to you for your whole life.
Also, keep in mind that in order to exert strength throughout the entire body, in other words to squat or deadlift massive weight, or to do the clean and jerk, the core musculature of the lower back and midsection have to be insanely strong - to allow the pushing muscles to carry through to the weight itself. Otherwise, it's like trying to push something with a rope - doesn't matter how strong the pusher is if there's a weak link in the chain. However, larger musculature means a thicker midsection, and a barrel chested man with a thick well muscled "core", even without the fat, is more likely to resemble a refrigerator than a bodybuilder's V-taper.
Conversely, Bodybuilders are really not as strong as they could be. Sure they're much stronger than the average joe, but due to the type of hypertrophy they cultivate, their muscle mass is made up of a lot of useless fluid. Bodybuilders also must exercise muscles which are very rarely used for anything except to have "defined" muscles, so they can actually be weaker, in practical terms (like the ability to lift things) than someone with an equal amount of muscle mass in more practical areas. A professional weightlifter's goal is lifting a lot of weight, so they work muscles which have utilitarian purposes. Fat also serves as a ready energy reserve for long-term activities, something a body builder lacks. Skeletal muscle preferentially burns energy from fat to save the sugar for nerve cells, and the "doughty" often have more gas in the tank.
The fat itself can also be helpful in a fight. Body fat helps absorb blows; one of body fat's main purposes is to absorb physical shock, which, while not as helpful in today's somewhat less violent world, has historically been of great importance when your fellow man wanted to beat you to death.
It should be noted that the idea that a strong man should have big, visible muscles in the upper body is a relatively recent one - warriors, as portrayed in art from many cultures around the world are often pictured as stout and heavy. It is, for example, not uncommon for paintings featuring samurai to show them having large bellies. The idea, in addition to what is described above, is that a strong, powerful body needs to be firmly rooted in strong legs and hips/stomach. Upper body strength is not very useful without a good support, and anyone who uses their strength efficiently derives much of it from lower-body muscles, simply because the muscles in the abdominal area are the largest muscle mass in the human body. While these muscles may, in fact, look quite impressive, a more "pyramid-shaped" body, with mass heavily focused in the bottom part, is less impressive to the average Joe than a guy with huge arm muscles and broad shoulders.