Don't know if these already have been mentioned but:

Filezilla or totalcommander are both great

totalcommander: I can't live without it. It has a fully functional "demo" for download, but I decided to buy it after all :shock: has basic ftp functions, and lots of other great functions for the ones that don't like the default ms control, but rather have full access to their own discs.

Filezilla: why look any further? It's free and it's (almost?) perfect.