We all have different styles, tastes and budgets, so there aren't too many hard-and-fast rules when it comes to investment bags. But we will lay down the law on this one (with apologies to all the vegans out there): It's gotta be leather. Investment bags are not made of canvas or nylon. Crocodile and python are great for those who have the means, of course, but the rest of us should stick with high-quality, sturdy leather. Shape, color and hardware are all up to you. Black or brown shades are best for versatility and longevity, but if you're dying for eggplant or fire-engine red, who are we to stop you?