Ive also sent this to Liz but you guys might be better placed to answer,
Got my Pi yesterday and not had much luck, every seems to boot ok but after a while (depending what is plugged in) USB lose power closely followed by Ethernet (about 15 second delay but happens everytime the USB drops) but the OS continues to run
I thought this was going to be the Power Supply based on the forums however starting to think its not, ive tried the following chargers
Official HTC 1000mah (using official HTC USB lead as well as trying a official Samsung one as well)
2x Official Blackberry 700mah (lasts the longest on this one)
From Powered Belkin USB Hub (not sure of ratings on this one)
My mouse and Keyboard are both 5v 100mah rated and have tried the above chargers with the Keyboard/Mouse directly plugged in and via Hub. For all of the chargers the voltage from GPIO headers never drop below 4.76v (using the Blackberry charger never drops below 4.84v)
Theres no set point where it will drop though without ethernet it lasts longer, but seems to drop quicker when the CPU gets used (and still drops even when idle after a while). However last night (talking after 6hrs of testing and trying to get it to work) it did seem to become more stable (still wouldnt accept ethernet though) its been mentioned on the forum it could be a faulty Polyfuse.
Full Forum Thread if you want to have a read is at http://www.raspberrypi.org/forum/troubleshooting/usb-bus-seems-to-be-shutting-down-after-30seconds
