I like the uncluttered look of the sidebar being hidden by default, especially for non-logged in users. My site probably gets a lot of one time check it out type visitors because of appearances at real life events and new users would be confused by the menu. Members know where to look for the menu if they need it and so I wanted it hidden by default.
Luckily Don made a really simple component that does exactly that
I use the featured topics component to do something similar
but I customize it with css - details here
I thought the drop downs also added clutter for new users and hide it and used the breadcrumbs component to aid navigation in the absence of the drop downs
link to breadcrumb component and my customization
link to hiding drop downs details
This sounds like this component might help
Not recommending my customizations as much as wanting to showcase how various available components and a little css can tailor the look of a Discourse forum and help it cater to individual communities and different needs