I bought the WD my passport essential 500gb, and have got it to work.
The only difference is I marked the Fat 32 partition I have for movies as Active.
I fromatted 33GB as FAT32 using swissknife, then formatted the rest of the drive as RAW using Windows Disk Management
Formatted it using WBFS manager as WBFS. Loaded games to it.
Connected USB port on the left of the Wii while Wii is upright and facing you(right one wouldn't work).
USB Loader GX works, I have also downloaded covers, and installed my DVD backups to the USB disk.
The only one I haven't had working is Wii Sports resort. WBFS manager imported it as 0.83 GB (which seems relatively small) (probably compressed?)
I ran it on USB Loader GX, and it came up with the 002 error, then I enabled the error 002 fix from the USB Loader configuration. Tried loading it again, and it takes me back to the Normal Wii Menu.
Am I missing something?