Best state for corporation?
This can really depend on the type of business you would be conducting, as well as your state of residence, among other factors.
For example, if you are selling products through a physical retail store/location, you will need to be registered in the state where the business is located. This is also true when your business owns or rents any physical property, such as a vehicle or real estate. Other factors can require you to be registered in a particular state, such as having employees, an office or conducting your business in person.
That being said, if you going to be operating an online business, you could technically register your business in any state you wish. Typically, Wyoming or Delaware are the popular states to incorporate in, and they are known as the 'corporate heavens' due to those states' business-friendly features.
Keep in mind, if you are planning on writing your business expenses off your taxes, it can create a nexus for your company in your state of residence, and eventually you may have to be registered there anyway.