I have a blog post template which, at the end of the page, I would like to show three posts that have the same tags (i.e. related posts), or if there are none, show the latest blog posts.

It feels like a combination of Taxonomies and Relate. The solution has to be user friendly, so Taxonomies feels like the better, more automated option for once there are many blog posts.

Has anyone solved this, and if so, how?

I just want to get your opinion before I start barking up the wrong tree.

Thanks :)