What type of flour is ideal for sourdough? I have found a recipe for sourdough starter culture that calls for 50 grams of flour with 50 ml of water, but the recipe does not state what specific type of flour you should use. Can you use any type of flour for the sourdough starter or are there types of flour that will give a better result? 

EDIT: I'm especially curious if Self-Raising flour would be suitable?
Tartine Bread by Chad Roberts (which is a wonderful book, by the way, and the bread is fantastic), recommends using a 50/50 mix of white and whole wheat bread flour.  He also says all-purpose flour is fine for a starter as well.

Self-raising flour would definitely not be appropriate, since it has baking powder in it.