The state in which it is best to form your new company generally depends both on the type of business you will engage in and on your goals with respect to your company.
For example, if you are opening a brick-and-mortar store it is generally most convenient to form your company in the state where the store is located, but if you are opening an online business, the world is your oyster, as they say. Similarly, if you are anticipating attracting venture capital to your company, then Delaware offers you the advantage of the friendliest and most developed business laws. If you would like to stay anonymous as the owner, New Mexico is the way to go. If you would like to take advantage of great liability protection and avoid high costs and a lot of hassle - Wyoming is a great state to start an company.
For more information, I invite you to read our article on choosing where to incorporate.