Is it possible to login via ftp to my dedicated server using a private/public key pair? i.e without using a password?
FTP can use SSL, which supports client authentication using X.509 certificates. However, while many FTP servers support FTPS, I don't know of any which support client certificates. (In addition, client authentication is complicated in SSL – in many cases, you would have to create and maintain your own certificate authority and stuff. Not many clients support this kind of authentication, either.)