I just ordered this off Crutchfield. cant complain 159.99 free Ipod cable. But the question I have is what HDD can I run with this. Nothing really big I dont have that many songs to put on it but I have a lot for now.
You can run any HD from what I know. The USB port supplies 500ma of power. So long as the HD doesnt require more than that power you are good to go. Other than that I think you can also buy a power adapter to power the hd. I think when you use the power adapter you use some sort of a "Y" plug. If you have a somewhat limited music library I think an 8gb flash drive would be best way to go. I just ordered 1 myself and its going into my Jeep Wrangler that I off road. I am sure all the bumps and vibration would wreak havoc on an HD. Just my 2 cents.
just got the X591 myself. i have a 40gig drive with 7gigs of free space, drive powers up with no problems. only thing you have to pay attentin to is that the HU only handles Fat16 and Fat32 file system. if you get a hard drive, you'll have to reformat to FAT32.