vagreangvbanyvmngvba ubrqbja (Score: 8,438,800,000)
The second one is invalid under some rules because its first word
is not found at dictionary.com (it should be, though).
I actually find the construction of three-word Googlewhacks more
interesting than two-word ones, because they make you triangulate relative unrelatedness of words. Two-word ones are more impressive once constructed, though.
Sat Feb 02 2002 20:49:
My two best Googlewhacks so far (rot13ed so as not to add search results for them):
onpxcbeg zheqref (Score: 53,118,800,000)