I had to do this once. I went on a trip to Africa with an organization where I shot tons of photos and HD video. In the end, I had over 100GB total, and they needed my source footage to edit videos and such. I lived in Florida, and the editor lived in Georgia. We tried dropbox, but that just was going to take weeks.

Our plan? He went to Best Buy, got a USB hard drive & mailed it to me. I loaded it up with footage and mailed it back to him. Once he got it, I think he was even able to return the hard drive and get his money back. The only expense was postage, and we saved a lot of time.