Have you looked at Joomla?
I am in the process of creating a massive, encyclopedic website using Joomla and with all the free plugins and components available it has done absolutely everything I have asked of it, including embedded video, images, galleries, PDF hosting, etc. Joomla is open source PHP software which doesn't require a knowledge of PHP to use. Like everything, it does have a learning curve, but a check of youtube as well as the joomla forums will sort you out in no time.
I use an old version of MS Frontpage for HTML design and then cut and paste the code directly into Joomla.
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Joomla! for more info.