I know most beginner bloggers really think if we need to use a HTML or an XML sitemap for the site? It is really confusing which one to use too. Here is a video of Matt Cutts (head of Google webspam) answered a question about HTML and XML sitemaps and what is preferred.
If you use HTML sitemap, Google will find your pages more quickly and this maybe a useful addition for visitors too. And an XML sitemap in not that relevant for visitors but Google would surely crawl your site but this does not guarantee that all the pages are indexed by Google.. Matt shows that if you really have to choose between an HTML and an XML sitemap you can best start with an HTML sitemap, this is because its useful for both Google and for visitors to your site.
Here is the official video below: