XML or HTML Sitemap is a guide for google to crawl and index your webpages smoothly.
If search engine crawl your site smoothly you have more change of ranking in SERP.

For fast indexing You must include site map

Yes we should submit sitemap because google's easily navigate our site and it's get help to ranking......Thanks,

Site Map is help the search engine to know about your site.I don't think it will make any effect to your site ranking but yes it is very important for your site,

Yes it is a good way to brink your web page to a good rank if you add a site map the Google will give more importance

Yes, sure! You should add site map!!

Yes, of course. Site Map is an essential part of any website. It enables the crawler to navigate your website.

Sitemap helps the crawler to your website fast.

Joe's post above is very informative. Having a site map is still a good idea, but not the end-all be-all that it used to be. But it can help you see which pages Google has indexed, which is handy.

More importantly (besides the obvious idea of good content) to make sure that your internal link structure is good and functions properly.

Yes dear you should create both XML and HTMl sitemap, XML sitemap helps search engines for indexing your website easily and HTML sitemap is for users.

Yes it will help you to get better ranking as Google prefer those sites which have XML sitemap.

yes, you should add sitemap to your website, its helps to your website

yes sitemap is very important for a website ranking in Google

Yes it will help.
Consider it like this: would you manage to get faster on a new terain if you had a map? If yes ... this also answers your question.

Hving Sitemap is helpful and beneficial for the website because it is the place where the complete site available under one roof with the all internal links and resources.

Site map creation is one of the main on page SEO optimization techniques.As a result, the users will come to know overall pages containing in a website.It is one of the plus point for search engine rankings,considered by google.

Yes, you can place HTML & XMl sitemap on your website. HTML sitemap helps visitors to know your websites navigation & XML sitemap helps to search engine crawler to crawl your website

Yes add a sitemap to your site. This will give the serach engines chance to index all your pages very fast.

yes, absolutely. It is invaluable and helps the search engines index your site