WD Passport HDD - any experiences?

It is definitely a power issue - and a big one at that.
The drive requires a bit over 1000ma to spin up - the USB standard (last time I looked) required a powered USB port to provide 500ma or better.
WD is out in left field with this product - one of their solutions is to buy an external power adapter, the other is to buy a special USB cable that connects to both your USB ports and can thus get enough power, 500ma from each.
The correct solution is to ditch the drive and get one that meets industry specs.

This is from the WD website

Just to make sure nothing had changed, I just looked at the latest spec on usb.org.

This is the introduction to the various USB hub and port concepts. 500ma or "5 unit loads" (at 100ma per unit is the requirement. WD is way off base here - interestingly enough they don't specify the current requirement under "Specs" for these drives and really downplay the issue.

googlefish said:

Disappointed - it's supposed to be Mac compatible. It's strange that it works on my Sony notebook that's 5 years old on USB 1.0

Click to expand...

Ironically enough probably because the ibook is a more sophisticated design than the 5-year old notebook.
These things sometimes backfire.

How many USB ports does your Sony notebook have? I assume at least two, maybe more.
Scenario A
To keep costs down, the older computers, Mac included, used a single USB controller for both ports - cheaper that way than one controller per port. The controller had no trouble keepting up with USB 1.1 speeds.
As for the power - the spec was 500ma minimum per port, so if I designed a 1 amp (1000ma) power feed to drive both ports in parallel, I would meet the spec.
The user can plug a 500ma USB device into each port - everything is great.

Scenario B
Firewire comes along and in response the USB folks need to up the speeds to be competitive. USB 2.0 is developed to provide 480 M peak speeds, outperforming firewire 400 at least on paper. But with the technology at the time, a single chip couldn't andle both USB 2.0 port, so an individual chip had to be rovided for each port. Power requirement is still 500ma minimum and that's what each 2.0 powered USB port provides. But they are individual ports now - the power is not paralled.
The user can plug a 500ma USB device into each port - everything is great.
Same as scenario A.

Well yes - as long as the connected device also follows the USB spec.

But for the WD drive, if you plug it into a USB port in scenario A, it can actually draw the 1000ma it requires, wheras in scenario B it can't and you have the problem you encounter.
In practice, a USB port will provide a bit more than the 500ma, the 500ma spec is the absolute minimum, but it sure won't be designed to provide 1000ma, especially on a notebook.

Does the WD drive actually have a USB logo on it? It shouldn't since it doesn't meet the USB spec.