Squarespace is the most user-friendly yet robust web design platform I've encountered. Squarespace also lends itself very nicely to the types of minimalist designs I'm after and is very easy for my clients to update on their own.
Squarespace is a website builder, blogging platform, and hosting service all rolled into one. Squarespace allows individuals and businesses to create and maintain websites and blogs. Their services are bundled so that each user gets a domain, hosting, and access to nearly all the templates and page styles. Squarespace offers robust tools for bloggers, artists, photographers, restaurants, and anyone looking for a clean, simple site.