Earlier quoted context omitted.
I personally swear by Total Commander[0] (previously Windows Commander). [0] http://www.ghisler.com/
I use http://doublecmd.sourceforge.net/ on linux, which is pretty-much a clone of total commander. I still like total commander better. As for open source - this one is, but it's written in delphi (pascal?) which makes it hard to contribute. Then again, it works well, so not sure what to contribute anyway.
Yes, I even have a copy of the Windows version of the original Norton Commander.
I used version 2.0 of NC in DOS 3 and version 3 in DOS 5.
I still miss the embedded viewing with Ctrl-Q that midnight commander is missing.
And I still prefer NC over TC, because it was so consistent.