While educating my self I'm having hard time to understand what an 128 bit AES key actually means?
Is it a key length or entropy?

Please explain to me trough following example (assuming AES):


  Password length in characters (L) = 20 (characters) 
  
  Symbols used (N) = 95 (ASCII set)
  
  Entropy = log2 (N^L) = 128 (is this what is called 128bit AES key?)
  
  OR
  
  Key length = L * 8bits = 160 bit key length ? (is this supposed to
  be 160bit AES key?)


When somebody says that he's using 128bit AES key, I want to know to what is he referring to, a key length or entropy?


Question: How many creatures should be in a draft deck?
Answer: Decks usually have a number of control/defensive cards, evenly balanced between anti-creatures, anti-instants, anti-enchantments etc.
I found more useful to put my attacking cards only in one category (creatures, enchantments, sorceries, etc.), so that a big part of my opponent's deck defenses becomes useless or less useful.
You can see that, if you follow this phylosophy, there is no "proportionate" or "disproportionate" number of creatures, but it would be rather more interesting having significantly more or significantly less creatures than "normal". Or even no creatures at all. :-)