Question

Which version of python should I use, 2.x or 3.x?

Answer 1

Definitely 2.x - the course is taught assuming you're using 2.x

Answer 2

I agree with that - if you want to follow the course, use the specified version.

Answer 3

For this particular course you need to use Python 2.5.4.

Answer 4

Any 2.x version should work fine (I'd suggest the most recent one). 3.x will cause trouble as some things were changed in that version which are not backward compatible.