It depends a lot on the information architecture / content structure. For example most of the time those three content boxes will be pulled in from a particular post type (blog entries or news or whatever).
I build non-blog-style sites all the time in Wordpress. The key is custom post types and custom taxonomies (so you can abstract the content out into as many different discrete types as you want, i.e. News, Blogs, Press, Testimonials, whatever) and then pull those into the page. Anything that needs to be directly editable can be accomplished by adding custom fields and tying them to that page template or post type. Combine that with as many different page templates as needed.
My two favorite plugins that make working with custom post types, taxonomies and fields are Advanced Custom Fields and Types. It's a lot faster and more convenient than manually coding them in your functions.php, especially when working with many post types and fields. You can add additional WYSIWYG fields, etc to accommodate as much content per template or post type as you need.
Widgets are the other common way to accomplish this sort of thing, but I usually avoid that and try to keep things centered around content type and page template unless there is a real need to implement something as a widget.