I wish someone could tell us what "Jaunty" did to "fix" this problem. I don't use Ubuntu, but I probably have this problem? It's REALLY annoying.

For me, I seem to have gotten it working by changing those aforementioned sysctl's AND changing my network device MTU's to 2200 (nothing lower seemed to work; (ifconfig wlan0 mtu 2200))

But I still don't feel satisfied -- not only don't I know what the problem was, but the "solution" seems like a hack :\.