python + Xml + GnuCash

[Somesh Bartakkay]

GnuCash -- popular accounting s/w is developed with c+Gtk+XML.
if i wanna develope application like gnuCash which handles flat file
database ::

1.weather it is wise decision to develope in python ? which is
prefered GUI from wxPython, PyGTK ? and Why ?
Shall i code wxPython in FUNCTIONAL programming way(nON Object
oriented) ?

2.weather i should go with XML or python's flatDB module which handles
flat file databse from python for storing data.

3.how i shold encrypt/decrypt my data which is going to store in
datafiles-- thru pythons..keep in mind that application performance
should b fast6..