Books: Core Python Programming vs. Python Cookbook

[Neil MacMillan]

I'm a 1st year computer science student, but I've been teaching myself
Python as my first useful programming language on and off for over a
year and a half.  I'm confident that I know the basic programming
concepts and Python-specific concepts, and I'm slowly working my way
through GUI programming now.  I don't know about threading, sockets,
and similar things that aren't applicable to a broad range of
applications.

I'm looking for a book in which I can find explanations and examples
for things like Tkinter, network programming in Python, etc.  Topics
that are covered in the official tutorial aren't necessary, but my
intelligence won't be insulted if they're there.  Mostly I want
something to which I can refer for ideas on how to do things better
and examples of things I never knew were possible (or at least I never
knew were simpler than they sound).

I've been going to the Chapters store and reading Core Python for
explanations of specific things that I needed to know, but the other
day I looked at Python Cookbook, which seemed interesting too. 
Unfortunately, Chapters recently took Core Python off the shelf, so I
can't compare them myself.  Chapters.ca has a 30% off sale, and I got
a $20 gift certificate for my birthday, so I can afford one or the
other (I might be able to make myself afford both if necessary, but I
won't count on it).  They're about the same price, so sadly I can't
decide on that basis.  If you please, which one would you recommend,
and why?  Would it be worth getting both?