Register a company in the US

Our company has started to market software in the USA and would like to keep a bank account there to lodge income from sales and to use for any marketing-type expenses that occur there. At this stage we do not plan to open an office.

My understanding is that we would have to set up a US-registered company for this.

Has anyone any experience with doing this? What are the tax implications? I assume Delaware is the best state in which to register?

Yes, it is very much necessary to get your company registered, because it has its own benefits. It gives you a name in the respective industry, you can market your business for a wider audience. Registering a company has become very easy these days, there are people who have made registering a company much easy.