I would have no idea either, but Ray Daniels refers to those beers in that way in Designing Great Beers.
No styles that I always keep around, but usually like to keep one of these types of beers:
Something hoppy (IPA, Pale, IIPA)
Something dark and roasty (dry stout, porter, etc.)
Something with a lot of yeast character (Belgian, hefeweizen)
Then I usually I have a store of big beers, like barleywine and imperial stout, also.