I have already preached the necessity of the the navy blazer and the grey sharkskin suit, and simply having both of those would be enough to get by fashionably from season to season, but you're not reading this to just "get by". So whats the next sport coat your closet needs that is going to become a staple in your closet for years to come?
Glen Plaid has been one of the most popular and classic check fabric patterns since its debut in the 19th Century. Popularized by the Prince of Wales in 1926, the pattern is most typically featured in the black and white or brown and cream color ways, and those two are the ones you'll want to stick with. Do the math, this pattern has been popular for over 100 years and hasn't experienced any hiccups thus far, so adding it to your wardrobe is safe and stylish.
|Thanks Nick Wooster for showing everyone how its done.|
Versatility is key with sport coats and there isn't a pattern that Glen Plaid can't handle; I'm pretty sure you could pair it with itself and you'd still look great. As for the choice between the "brown" or "black", look at your existing sport coat game, if you already have a khaki or light brown jacket, go with the black and white, and if you have a couple grey suit coats, go with the brown Glen.