HID's or LED fogs must be for "pretty". If you want FUNCTIONAL fogs, you'll need a 3000k or 2500k lamp and I'm not sure you'll see HID's or LED's in that range.
I've dealt with a lot of dark, wet or dark, snowy nights and anything from the stock halogen lamps (~3500k) on up are garbage for seeing that short, wide throw that fog lights are supposed to provide. The lower Kelvin lamps provide much better contrast than higher K lamps, I don't give a ratz azz WHAT MythBusters says.
...yellow up high IMO looks atroscious compared to a 4300K, which still provides a very significant improvement from stock halogen.