[Pictured: Timex tank watch complete with, yes, Indiglo.]
Cartier introduced the "Tank" wristwatch in 1917 during the first World War. It is easily their most storied model and was designed by Louis Cartier who was inspired by the new American war machines aiding the fight in Europe. His goal was to create both a beautiful yet rugged timepiece and the design is now considered an undisputed classic.
Either you can afford a Cartier tank watch or you're like me and it's, give or take, a thousand dollars out of your price range. While the original classic is a bit out of reach there are a bunch of great options available as the style has become a mainstay with many brands. The understated elegance of the tank watch doesn't mean you need to spend the big bucks so if you're in the market for a good looking watch that gets the job done any one of these should work. You can also try eBay, but be prepared to bid with the big dogs as lots of the available watches are vintage, high quality options. Don't forget the best way to take a cheaper watch, say a Timex, to the next level is to throw on a new strap to personalize things. If you have come across any other affordable pieces in your internet travels feel free to throw 'em up in the comments.
Timex...$24.00 (as seen above)