Works:
Western Digital My Book Essential 1TB
Problems:
Eagle Tech Consus T-Series 2TB (USB 3.0)
– this drive is not recognized by IOS58, but is by IOS202. I have been able to get WiiMC to see it by loading WiiXplorer in IOS202, exiting it, then loading WiiMC (seems to continue to use IOS202 for USB). This drive WILL work with Geekbox, MPlayer CE, WiiMC 1.6, and various other IOS202 apps.