I just discovered a great site with Free stock footage! http://xstockvideo.com/ Make sure to read the agreement before downloading though. Its free for everything, but there is a couple things you can't use it for.
I downloaded a 30 second clip of just clouds in 1080p and I thought it looked very nice. So go check it out! Free for commercial use as well! Can you tell yet that I like free stuff? Ohhh Yeah.