I assume you are talking about a Wii not a WiiU. I can't speak for the WiiU but on the Wii I recommend a Western Digital My Book Essentials. I have the 1TB model. Format it to FAT32 using the tool from ModMii. This drive is compatible with everything. I run USB loaders, UNEEK, triiforce, RawkSD, all emulators, homebrew and wii-linux with no issues. With Western Digital HDDs there is a tool to turn off spin-down,you'll need to do that first.