My Raspberry Pi server just got another update, again. Because of the death of poor WD Elements HDD, this time the 1.5TB Seagate GoFlex is now become new member of the harmonic family:) HDD's auto spin down has been disabled to solve problem that may disconnect under Linux and cause data lost. Because router's USB port is not used so Pi's canned spinach is now supplied by AirPort Extreme. Actually, AirPort is not beefy enough(just a little behind) to power the HDD along with another adapter therefore the 700mA wall-plug adapter is switched to power the HDD. Both power source powers Pi via USB port directly. Since Pi is no longer stick at the back of HDD so the HDD can be easily umounted and move downloaded files to my computer. Unfortunately HDD is such a power consumer that when it's attached on a running Pi, the Pi restarts, as always.
P.S. How sweet if next Pi has a better SoC with GBe and USB 3.0...