I have been monitoring the server performance for the last several weeks (and experiencing it myself while surfing my own site) and it was not up to my standards. I previously attempted to enable APC to speed performance up and failed numerous times for various reasons, becoming frustrated in the process. Today, however, I thought I would give XCache a try with great success. It looks as though CPU usage dropped by around 50% while page rendering and crawl time also dropped by 50%. I am pretty happy with the results.
Now, I can get back to converting my Wiki content over to WordPress so users can experience no ads while logged in and comment directly on Service pages.
An example of converted content is here. It is still a bit rough around the edges, but optimization will come in time.