There's always Behance: http://www.behance.net/
and Vimeo has a ton of gems as well.
I would suggest going to a site like Feedly or any RSS aggregator—a place that lets to follow multiple websites/blogs—and start keeping tabs on these sites (and more!). There are TONS of great graphic design and motion graphic artists and websites and these sites will help you keep up with the new stuff. I use Feedly to follow a number of topics that I'm interested in as well as some of my friends. When new articles are posted it lets you know right away, so with a glance you can see how many new videos a certain website has.