Do you need an on page site map as well as an XML Sitemap?

[bonnierSEO]

Do on page site maps help with SEO or are they more for user experience? We submit and update our XML Sitemaps for the search engines but wondering if /sitemap for users is necessary?

[Branden_S]

yes you should use both.

You should also have an xml sitemap for video.  I recomend using Wistia if you have a good budget, since they automoatically create video xml.....otherwise use Vimeo Pro, if you are on a budget.   http://www.seomoz.org/blog/hosting-and-embedding-for-video-seo

And an xml sitemap for your blog (Google News xml sitemap) ... if you create lots of articles and want your articles included in Google's news feed. http://www.seomoz.org/blog/how-seomoz-gained-1000s-of-visits-from-google-news

[yeagerd]

In my experience, the html sitemap does not effect SEO as far as indexing the site, assuming you have good XML sitemap and a good link structure.  I

I would say that the sole reason to provide an html sitemap is UX, but that is a huge reason to do it.  Anything that upgrades your UX, also has the potential to boost your SEO.

Making the full site easy to see and easy to explore will encourage longer site visits and more page views, and that effects your value in the eyes of the search engines.

To expand on what Branden said, specialized sitemaps are a very good idea.  Seeing as you were hoping to get rid of a sitemap this may not be what you want to hear but you really should have a sitemap for each type of content you have.

Mobile | Video | News | Images | TV Shows and of course your general web sitemap

Take a moment to learn about each of them as you will want to understand each maps expectations.  ie. You should never have anything on a news sitemap that is older than 2 days and Google will reject anything that does not meet it's criteria.

Here is the Google Resource that explains it all.