choster - 3:57 pm on Dec 9, 2009 (gmt 0)

I suppose it somewhat depends on your needs— what protocols, what level of security, what command line options, and so on. We use both WinSCP and Filezilla, both freely licensed. WinSCP has an edge on features (superior integration with PuTTy, Windows shell extensions, SCP protocol) while Filezilla has a more configurable user interface.