I have a G-Drive 250GB that works great on the Alu MB via USB bus power (no Y-cable needed, no AC adapter). I bought a 500GB G-Drive but it only works with a Y-cable on the MB, and does not work at all with my Xbox 360...the 250gb works fine with the Xbox. I bought the 500 specifically to transfer movies to the Xbox from the MB, so I'm bummed it doesn't work. An AC adapter would of course work, but it's not practical given my setup. Logic tells me that if a drive works with the MB, it should work with the Xbox. So, I'm wondering if anyone has another brand of 500GB...WD, Seagate, etc. that works on bus power with the Alu MB. If no one can confirm a 500GB works, does anyone have a 320GB working? Again, I'm looking for drives that work on bus power only. Thanks.