I bought a WD My Passport Ultra 1TB for Windows because I was only able to find it or the MacOS version in the stores, because it had good reviews and good price < US$60
The cons is that it is not good for Linux backup out-of-the-box because NTFS does not preserve ExtFS ownership (user/group).
The second bad news is that gparted will not be able to resize the installed partition not even if you try to use Windows in virtualbox. Actually with virtualbox it will not be able to mount the formated partition.
So you will need to use a system with Win 7 so you can use a Windows partitioning program (eg. Partition Programs) and than resize the factory installed NTFS "data" partition.
The new size should be, say, 24~340GB ( leave this space so you can exchange data with Windows (your friends or family) and to keep the special features of WD that are native stuff to Windows and avoid it from causing problems (or void your warranty).
You should now create the new Ext4 file system with the empty space, but also reformat the NTFS partition, because the native version is not correctly detected or mounted with ntfs-3g.
I choose the names for the partitions below to be easily identified.
At the end of the process you should have something like this:
1) WD_NTFS with about 32 GB
2) WD_EXT4 with about 968 GB
3) Also, does not show, but there is a hidden partition (like a CD-ROM) that WD stores the special crypto stuff and firmware copy (this is what my research found).
The lack of capability of gparted to handle this type of filesystem is really frustrating. How can this be true with so many talented people in our GNU community ?
Also, I understand now that WD really ignores Linux users. This is a sad situation since most users I know and worked with, for several years, are all Linux users and we usually choose WD HDD, at home and at work. But, from now on, I will start to choose new brands that support linux users (WD do you hear me now?!). And you should too.
I bought a Seagate 2T similar size at < $70 and was able to use gparted to resize and create Ext4fs with no hassle. Seagate "hear us Linux users" better.
Proud Linux User.