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i'd agree with Klarke, the first choice should be .com because people just assume that extension with domain names so you might miss out on traffic  If the domain is not available, then you can choose either the .net or .org .

For me it is important that it doesn't hurt my rankings - I don't believe that I can boost my ranking by adding H1 twice on the page, that was not my intention. Good to know that I'll be on the safe side - still Thanks people.