I do not ride with goggles, nor do i generally ride in bad weather (i know i am lucky!) but there is a guy in this part of the world who swears by habervision eliminator goggles.
They have a little battery operated extractor fan that apparently stop any fogging prob worth checking out if you need to keep your gogs on all the time
http://www.habervision.com/goggles/e...orgoggles.aspx
http://www.youtube.com/watch?v=3nYiNDgLxAE