design question - pages or posts

Hey all. So, i'm building a site which is meant to be a kind of informational encyclopedia about a topic; which is very heavily graphical. I'm hovering between using 'Posts' and 'Pages' to describe the various bits. They both seem fairly similar, save that Pages do not have the Next Post/Previous Post aspect built-in; and that I have seen plug-ins that enable me to change the menu on different pages.

It may be an arbitrary thing; but the design, on the base level, is what i'm on about. It seems that if I add categories to PAGES, then I can organize them just like posts and it's easier on my back-end. And that I can use the 'show menu' 'do not show menu' or other options within the pages.

I may be going on. I suppose everything can be solved with plug-ins. Either way, it's essentially wanting to have certain Pages/Posts that are relative to certain bits of information and then have other Pages/Posts relative to other; and having control over whether the menu is shown on a page and what is included in the menu.

Where is a plug-in that removes the menu from certain pages/posts?