> During research I stumbled across Khttrack; could someone 
> explain to me the difference between HTTrack & Khttrack? 

Khttrack is a Linux/Unix frontend (using KDE) for httrack 
(commandline) ; similar to winhttrack, but with fewer 
options for now

> Should I use Khttrack together with HTTrack? Perhaps I am 
> mistaken, but the interface in HTTrack seems to me quite 
> the same as shown in Khttrack.

WinHTTrack : the most complete GUI for now, but ONLY works 
on Windows platforms
Khttrack : a GTK frontend (linux/unix, but NOT windows)
ghttrack : a Gnome frontend (linux/unix, but NOT windows)
httrack : the commandline version (dos, linux, unix)

The next release, 3.30 (currently in development) will add 
a new version
WebHTTrack : a complete GUI for all platforms (linux, unix, 
but also windows)

For archiving purpose, winhttrack is good to configure, but 
if you have to setup automated jobs, using the httrack 
commandline version might also be useful (and using unix-
like scripting)