New York Post may receive revenue from affiliate and advertising partnerships for sharing this content and/or when you make a purchase. Of all the school supplies, a back-to-school backpack may be the most essential. Sure, new jeans and a pair of spunky new shoes are important too, but what will you store your laptop, books and lunchbox in? Will you opt for a pretty floral print backpack or a skater-boy checkered vibe? Whichever you go…