My earlier praises of divShare have lost their shine due to the ongoing frustration of pop-up adds. Simple enough to block, especially using a browser like Firefox, but no user should have to worry about them, especially students focused on their learning. So instead I have begun using Vimeo, a fast and sleek video sharing site with a little social networking thrown in for good luck.
I can upload mov and m4v files which is perfect for a Mac user and upload up to 500MB per week including HD movies. The quality and speed is excellent and the interface user friendly. Additionally I can embed movies in any ePortfolio using the excellent Video Embedder plug-in.
At this stage, highly recommended.