If you have been on the forum for a litte while, you know that we cannot answer this question, yet we all wait with anticipation. to get the answer. LOL
HTML 5 is not the panacea for all devices - think more it is a development from previous versions which, among other things, tries to standardise presentation of multimedia rich websites in a less kludgy manner.
You still have to design a site for your target viewers equipment ie computer, tablets. smartphones etc so you still end up with multiple versions of the site.