I've let the site sit for about a week or so. I wanted to make sure the increase in traffic wasn't simply due to chance.

Here's an update:

Page rank - 0/10
Average visitors per day - 147

The page rank is still the same. But the average number of visitors per day has risen by 43 since I started this test. For such a simple change that's pretty impressive.

Now I'm going to apply the next of Nathan's tips.

Colin