It appears that immediately after waking is the best time to write – when your purpose is not already acquired. Acquired, you may continue on through the night, but not the other way around.
I myself am an effective night-owl, but only when continuing to work on something began much earlier. When I try to start something new late it’s pretty much guarenteed to fail. Might as well watch TV, or better yet, go to sleep. On the other hand, after several years or trying to write a bit on this blog, I have realized that the bulk of my best stuff was written early in the day. Sometimes very early, when I coudln’t go back to sleep after the baby began fussing.
“I write only when inspiration strikes. Fortunately it strikes every morning at nine o’clock sharp.” – W. Somerset Maugham.
In other news, when I am completely and utterly lacking in creativity, the pages of my notebook end up looking like this.