I use jMethods JFTP from jMethods
http://jmethods.com/jftp/(Requires Java)
I use '@JAVAW.EXE -jar -Xmx256M jftp-5.0.1.jar' to run it from a cmd file with Java6.
Main reason I use it is because that happens to be the one I settled on to run with
AIX, and it also happened to work fine under OS/2 (though the start ups a bit slow).
The largest file I've transferred, I think, is about 8gB.
Otherwise for hobbes stuff I prefer EmTec's FTP client simply because it's fast
but it has problems connecting to Mac's, some other FTP servers, and has the
standard file size problem due to it's age. <== Probably also due to my extensive
FTP bookmark's, I'm to lazy to copy them over