Archetype and Content Blocks are great for flexibility.
A simple Umbraco 7 teacher resource making use of flexible "content blocks".
The Food for Life Scotland Toolkit allows content editors to build flexible pages by stacking separate pieces of content.
A proven technique that I've used a number of times which gives editors this flexibility is the use of Content Blocks.
Simple content blocks are stacked up on top of each other in order to build a complex page
Archetype (a package for Umbraco) allows you to define blocks of content and order them.
This works well, giving content editors the flexibility to build a wide range of pages and know that everything will be displayed correctly. The not-so-great alternative would be to use a single Rich Text Area but this can present and number of problems with regards to layout and styling.