For those of you experiencing shaky WiFi connections:
Half the problem is Windows.
Try this [http://www.speedguide.net/downloads.php]
If you know what you're doing, you can bypass the retarded settings that come with Windows and dramatically decrease ping and increase stability.
If you don't, click optimize and it should help a little.
Also, if your router is trying to renew your connection every few minutes, increase your lease time.
Most routers will go up to at least a week, others will go to any set date (just put in 10 years in the future and you'll be fine), and still others allow a permanent lease (this is static DHCP, if you don't know how to use it, learn).
For OP, try various connections.
As we can see, your local connection is excellent, however try California, Ontario, Alberta, Japan, China, Russia, Great Britain, Central Europe, Africa, and South America.
If you notice a big drop (or increase in ping) anywhere (especially if it 'continues' in that direction), then there is likely a problem with a server along the way.
If you believe it to be nearby, contact your ISP and ask them if they are aware of the issue and when (or if) a fix is expected.
If you're having problems a fair distance away, there's nothing you can do, unfortunately.
Also, yes, before anyone asks, I can verify that Windows is half the problem - I have an Intel Mac, and I often get the exact same symptoms you describe when I'm running the Windows side, but never on the Mac side.