FileZilla is a powerful FTP-client for Windows. It has been designed for ease of use and with support for as many features as possible, while still being fast and reliable.

FileZilla Features
Ability to resume Uploads/Downloads (if the server supports it)
Custom Commands, Site Manager with folders
Keep Alive system, Timeout detection
Firewall support, SSL secured connections
SOCKS4/5 and HTTP1.1 Proxy support
SFTP support, Upload/Download Queue
Drag&Drop, Multi-language support
GSS authentication and encryption using Kerberos