During my morning web crawl i stumbled on a post at paulspoerry.com which covers how to analyze Wordpress performance with Firebug. This was an application of Firebug that i haven't thought about even though I've been working with web development and Firebug the last couple of weeks. In my defense the projects at work aren't focused on performance at this point.
Anyway, when i ran Firebug on this blog i noticed that it spends a lot of time searching for an image that doesn't exist. By simply removing the reference to the image from my theme i decreased the loading time by almost two seconds. That's around 50% of the loading time so in my case it turned out to be well worth the 10 minutes spend.
I would like to run Wordpress in a PHP profiler to see why it takes so much time getting a page. I'm already using a cache plugin so the page rendering shouldn't be a problem.