I reccomend SkyDrive. It's free, all you need is a Hotmail or Windows Live account and that's free too.
I even use it to host and "stream" video for my blog:-
http://www.timacheson.com/Blog/2009/oct/hosting_video_and_web_apps_on_skydrive
SkyDrive serves video extremely fast, and any other file type too!
The next level up from SkyDrive is Azure, starting with Azure Storage. There is no official storage limit on Azure, but anecdotal evidence indicates hundreds of terabytes:
http://www.timacheson.com/Blog/2009/sep/azure_preview
