I need to display both a portfolio and a blog on a website, and as a relative newcomer to WordPress, I was wondering what the most effective way is to do this: install a plugin, or create a multisite?
Essentially for the portfolio page I just need to display a thumbnail, category, and title, but when each entry is clicked, I need a full, blog-style post. Is there a plugin that will do this, or would a multisite (ie, running the Portfolio as a separate blog) be easier?
Set your blog as Blog category and your portfolio as Portfolio category.
You might be also interested in Custom Post types (which I think is the right way to do it):
Run your Blog as a usual via Posts and set the Portfolio as Custom post type with its own categories, tags or what ever taxonomy you need.
Read more here: http://codex.wordpress.org/Post_Types
Multisite is a completely different concept.