Which CMS/engine should I choose?

I need to create a web-site for a client that focuses on providing hardware maintenance guides and tips.

So basically, it’s sort of like a big database of different manufacturers, hardware models, etc. Each model has a stand-alone page with images and description, comments.

First I considered Drupal, since it’s supposedly the most flexible system out there. But having played around with it a bit, I understood that the client, who has little experience with managing web-sites, will have a hard-time adding new content.
Then I thought about Joomla, Mediawiki, Wordpress. And now I’m just confused.

Basically, what I need is a CMS that’s light-weight, easily customizable, user-friendly (has an backend even a newb would handle), offers toggle-able user-group permissions, and can harbor tens of hundreds of pages without turning the site navigation into a mess.

Any ideas? Suggestions? I’m desperate.