I've recently converted my site over from a custom built system to Wordpress as I'm learning more about it also as I'm writing a few plugins it makes sense.
Anyway since I converted the site over I noticed the pages are taking a lot longer to load then they should. At first I thought it might be my server so I looked at other sites I host that are on the same server box they were all fine.
I installed a cache plugin in case it was the content but that made no difference I even tried turning off all my plugins in case one of them was causing the delay.
Nothing I had tried thus far made any difference or gave an indication on the problem I thought it might be the database calls but it turns out I was calling a few font-face in my CSS file that I forgot to upload so the delay was caused by the browser trying to load fonts that were not there!
I only found this out after I ran my site through a page load time tool from Pingdoms Tools http://tools.pingdom.com/fpt/
This is an excellent tool! as I scanned through the results I could see right away what the problem was once I corrected the missing fonts my site started loading much faster.