Wow - that's really, really great list.

In particular, #7 is something that I didn't even know existed, and I've been hacking around for 2+ years.

Instead of:

   mdict={'gordon':10,'tim':20}
   >>> print mdict.get('gordon',0)
   10
   >>> print mdict.get('tim',0)
   20
   >>> print mdict.get('george',0)
   0

I've always done the much more verbose:

   class defaultdict(dict):

       def __init__(self, default=None):
           dict.__init__(self)
           self.default = default

       def __getitem__(self, key):
           try:
               return dict.__getitem__(self, key)
           except KeyError:
               return self.default

   mdict=defaultdict(0)
   mdict['gordon']=10
   mdict['tim']=20
   print mdict['gordon']
   10
   print mdict['tim']
   20
   print mdict['george']
   0

I'll be sure to make great use of the dictionary get method - I'm embarrassed to admit how many thousands of times I could have used that, and didn't know it existed.