SEO/Usability Drop down menu and folder/file structure?

I have never actually created a site with a drop down menu until now. Which has got me thinking of which is the best structure for the files. It prob makes little difference but it’s worth the effort for me.

Originally I just had all my files strait off the root. But now I’m thinking… if I have a drop down for a section then it may be best to put all those files into a folder so…

Services

      • sub
      • sub

Typically the further files move from the root less importance they are deemed I believe. I base this on things I’ve read and the default importance value sitemaps give to files. So that may be worth considering.

Anyways… how have you guys done it or do you have any thoughts on all that?

It is looking good till now but when you put your content deep in folder then it will not be good practice.