I had a similar problem getting to Planit3D a couple weekends ago, but that was apparently server-related. I also tried everything you listed above in hopes that it was just my machine or net, but nothing at my end helped. Once Monday rolled around and somebody reset something all was fine. Have you tried a ping to the server or get something like Trace3D from snapfiles.com in the network apps section and see if you can trace a route there at least. Cooler found a suspected problem when he trace-routed to P3D and found a server inline with an 80% packet loss. I tried NeoTrace but that didn't report the stalled server for me, Trace3D did. One last idea, you could delete your cookies for those three sites and see if that helps (once you establish that it's not a server or hop problem).