Great tutorial, for a fast Python start up.
I would recommend starting with python2.7, if there is not a specific reason for 3.x .
At last I would like to point out that in the most Debian based Linux distros python2.6 and python2.7 will be pre-installed normally at least both are pre-installed on Debian stable itself.
Cheers!
Helpful Note
On Debian based Linux distros you can install idle as a starting 'IDE' with : apt-get install idle-python2.7;