It shouldn't. If you're selling, you want the law that applies to be the law in your jurisdiction. If there's a problem, you want to sue them locally rather than travel to the US (either directly or through a legal proxy) to sue them on "home turf")
Something like "The above Terms shall be governed by English law. You agree to submit to the exclusive jurisdiction of the courts of England to resolve any legal matter arising from these Terms." should do the trick. (remember, I am not a lawyer nor do I play one on TV)