Hi,
http://motionographer.com/ is a good start. Under "Cream of the Crop" are links to a lot of graphics companies with demo reels and what not.
Also, don't discount print graphics as sources of inspiration. Communication Arts magazine is a great resource for very well done graphics. I often browse the magazine for visual treatments that I can adapt into a motion graphic.
And then there is the real world. Look at the patterns of rain on the side of a building, shadows through a tree, car lights at night etc. Think about how you would change something you see in the real world to something more idealized or stylized for use in a graphic.
Getting inspiration is difficult. It can be exhausting to try to stay in a mental state where you are constantly seeing visual possibilities all around you. One way to help improve your "seeing" is to carry around a sketch book and to get in the habit of drawing things that look interesting. Photography is also a good "sketching" technique. By developing habits such as these you keep you mind open and on the look out for interesting visuals in the world around you.
Hope this helps,
Lars
