An interesting thread. I'm still trying to figure this writing thing out. But I'd have to say, my most common inspiration comes from reading.
Sometimes it comes from when you read something and say to yourself, "The author got it all wrong!". Other times, something I've read makes a connection with me in some way and sends my psyche down a path I've not been before.
But I'd say my inspiration is almost always a string of text in some way.