I was taught the Disney[/url] approach to gathering new ideas.  Capturing ideas without judgement is a very good way at accumulating a lot of ideas really quickly.  If you try and judge ideas as you go along then you might get 3 or 4 ideas that are, at best, evolutionary.  Capturing without judgement might give you
  4 evolutionary ideas
+8 barking mad ideas
+2  promising lines of investigation
+2 Radical and revolutionary ideas
16 ideas, 12 more than you would have got.  Who is to say that the really great idea won't be the 9th, 11th, or the 16th?  You'd be really lucky if it was in the first four!

For me the important thing about new ideas are that they give us something new to talk about, an opportunity to find common ground where entrenched views and approaches are a barren and hostile landscape.