http://webpagetest.org is also pretty good at measuring speed. It will also show you when page started to render in certain browser and what caused the delay. Great tool. Try it there and share your findings.
Seems like media compression is going to need to be your priority. I'd also see if you can change anything to static HTML to see if you can reduce the overall queries being done to databases (like the links on the right). As a random side note, just for visual appearance, don't forget to change the alt tags on your images - they still have funky mouseovers
One issue with page load speeds is your advertisements... this is something you really do not have much control over if your ad server or ad network is serving ads that are resource intensive. Is that true??? IS there a way to optimize ad loads and it effecting over-all page load times??