include based on custom taxonomy

I’m trying to show a particular include based on a post’s inclusion in a custom taxonomy. Can someone point me in the right direction?

In other word, here’s what I’m trying to do:
1. user clicks on a post
2. page checks to see what the post’s setting for a particular custom taxonomy setting.
3. Based on the posts custom taxonomy setting, code further down in the page calls a particular include which shows navigation links appropriate for that custom taxonomy setting.

Thanks!!