I think it's worth creating a sitemap for navigation purposes as well. It's not very difficult and allows for easy, fast navigation of your site's most important locations from a single point.
Take a look at mine:
http://www.modernflat.com/sitemap/
I use wordpress and creating this sitemap (it's a PAGE, not a post) took all of 5 minutes. There isn't much to it... just a call to grab the PAGES, CATEGORIES, ARCHIVES. Created 3 lists, floated them one beside the other... done!