I was looking for a quick way to recursively download the entire FTP directory for a site that we are transferring. This was, I found, the easiest and most straightforward way:
On the command line interface, assuming you have wget installed, type:
wget -r ftp://USERNAME:PASSWORD@mysite.com/
Hit enter and wait while it retrieves everything for you.
I did it this way because I didn’t want to download 4gb of data to upload again, so ran this command direct from the ‘production’ server with its stupidly fast internet connection. Hours and hours saved!