How can I download a specified directory and all it's files from an FTP server (requiring username+password)?
My personal preference is
You can install it from the repositories by typing
It's quite stable and with plenty of features.
Alternatively, if you want to download by using a shell FTP client (no GUI), you could try to use
Open Nautilus, select File > Connect to server.. Select FTP with login. When you're logged in, right click the folder you want to copy and paste it somewhere on your local system.
No need to install stuff. You have everything you need. :)
A few command line solutions from this thread on SO:
Might not always work, as per SO, so try
This one is highly recommended over plain FTP.
Any FTP client is able to download directories recursively and also authenticate with a username and password. Just start Ubuntu Software Center, search for "ftp" and choose one of the options.
Filezilla looks like a good candidate to install and see if it works for you (though I never used it).
Or do you mean you want to download files in some unusual way (in a terminal, from a shell script, etc.)?