Let the hive mind of Engadget get that for you.
"As someone who doesn't reside in the USA, I was wondering what would be the best way to get internet for my computer in the US for a couple of weeks? If it were Europe I know I'd look for some prepaid data. Is there anything similar offered by American carriers? A MiFi or a data SIM that I can tether from would work, but I'm trying to maintain a tight budget. Help!"
WD Passport's power supply is a big problem. They only give you a standard MiniUSB cable and some computers (actually, many computers, in my experience) don't provide enough power for the drive to spin up.
My friend's WDPP 120G works on 3 of my 5 computers but not the other 2; I got another 120G from Circuitcity (memorial day sale) and none of my computers work with it. Had to return it and grab a Seagate FreeAgent Go instead. So far I'm happy with the Seagate drive. It comes with a Y-USB cable that allows you to get power from 2 USB ports, which most computers even laptops can provide easily. With this Y cable, I have no problem using it with all my desktops and laptops. For WDPP, you'll have to buy such cable seperately, which is about $10 + tax + s/h.
wd doesn't suppy a Y-cable? That's pretty bad. Even the cheapiest of cheapie external cases (one of which I'm using) provides those.
I'd be ineterested to know what make/model of USB-translation chip the WD external cases use, but if they don't provide a Y-cable (or extra cable, as some do) for additional power, I don't reckon I even want to know.
There are a significant number of computers (and some higher-capacity HDs), as samson said, that won't power the external drive properly without an additional USB plug plugged in. The WD Scorpio 80GB is at the limit of what the USB bus can theoretically provide, for instance).
Add some deviation from the mainboard and you fairly often get a drive not working on some computers - until you plug in that second usb plug.