Best method of transferring files over internet? [closed]

I'd choose rsync over ssh.

You get encryption that way and rsync is smart enough to resume partially downloaded files and to copy only different files to avoid excessive traffic usage.

The first thing that springs to mind to me is that I don't think that SMB will allow you to resume a download - which would be a real pain if you had a problem 16.5GB through a 17GB file...

So I would go for FTP, something like the pure-ftpd or vsftpd servers, both of which I would guess would be in the Ubuntu repositories if it isn't part of the standard install, and both of which should be relatively simple to set up securely; see here for an example setup for vsftpd.