I absolutely, positively second DropBox. It integrates seamlessly, and you may have 100GB for only $200 a year.

But th best thing is that you can try it for free: it gives you 2GB initially, and an additional 250MB (up to 10GB) for each new user you refer. (E.g. if you apply via this link, I'll get an additional 250MB: http://www.dropbox.com/referrals/NTIxMzc2ODk _hint hint ;)_ )