Your mom is right: In the winter, it's all about layering. Smart men know that a pair of wool pants is not enough when temperatures start nearing freezing point. If you get a bit chilly down there, your best ally is a pair of long johns. As opposed to synthetic fabrics, such as polyester (which only makes you sweaty and stinky), opt for natural yarns like cashmere or wool. Though the most luxurious cashmere options go fetching in the three-digit range (if you're willing to splurge, try The Eighth), Patagonia's merino wool long johns offer a great compromise, blending the warmth and softness of merino wool with the extra-breathability of a trademarked Capilene fibre. Think about how cute (and comfy) you'll look wearing just these by the fireplace.