InForm is a CMS that is designed to provide most of the tools that you need to manage a website out of the box. It provides no restrictions or constraints on how complicated or simple you want to make your information hierarchy and provides options to let you re-organise your data in the future if so required.
The fiennes.org website is entirely built and maintained using InForm and has no custom code other than the presentational layout.
InForm is primarily a tool for organising content. It may be used as a blogging tool if required, but primarily it is about giving easily updatable rich pages of content to let you express yourself as cleanly and easily as possible.
InForm is a re-usable tool that can be utilised on many different projects. It should be flexible enough to be able to let you model a wide range of information out of the box and therefore is a very cost-effective route to web.
The basic page type is a "content page", which unsurprisingly enough holds content. However the system provides quite a very flexible document layout engine that lets you style your content, and embed external functionality into your pages.
A News Feed is useful to publish news updates or blog style posts. InForm will deal with all of the chronological navigation and archiving of the stories letting you concentrate on the writing.
An event calendar lets you organise information about future and past events.
An image gallery automates the process of generating overviews and navigating around collections of images.
InForm comes with no constraints as to how you organise your information hierarchy. You can make your page hierarchy as wide or as deep as you require, and you can nest page types inside each other as required, for example you could have a story in a news feed that contains a gallery of pictures about the story.
If you decide in the future that your current hierarchy is not correct, then you can move and copy pages around freely within the structure, and InForm will keep track of both internal and external references and ensure that you don't get any broken links from references to the old structure.
If it turns out that after using InForm for a bit that you want to have it customised and extended so that it understands and models your business practices directly then this is entirely possible.
However my experience is that it is better to start with InForm and get a feel as to how your online presence is going to be structured and what works and what doesn't work for you. This way you can build up a concrete case for and against commissioning custom extensions based on real-world experience rather than designing everything at the outset.