Sorry not to have responded to this thread before, I 
did not have enough time.

The idea of an improved explorer-like HTTrack version 
was in fact already suggested (not as detailed as here 
however), and I started to implement a treeview to do 
that purpose. The problem, is that I did not have 
enough time to code all routines and necessary changes 
in the engine (the main one would be to 'pause' the 
engine even if no links remains on the stack).

The second reason was related to the tool used to 
develop WinHTTrack: Visual C++ is really not the best 
tool to code GUIs (just look at the WHTT code if you 
don't agree ;) ): use of MFC's (abandonned by MS), non 
portable, complex to implement, many bugs.. 
In fact I wish I could use Kylix/C++ to recode the 
interface (but this product is not yet available, 
unfortunately), which would be available on both 
Windows and Linux, and much easier to code. 

I am now trying to think of a complete recoding of the 
GUI, and waiting for Borland (hurry up, guys!)