"There are rumors he is in to field hockey players"
Which is taken literally from the conversation between Kim Deal and David Lovering before the song I'm Amazed on the Pixies' album Surfer Rosa.
Surfer Rosa, hmm, I think I'm onto something...
BTW I think Black Francis is a closet Malkavian. Anyone ever tried to make sense of his lyrics?
And another one is when you talk to Isaac about Ash (and him not willing to help Ash) you get a dialogue option:
"Ashes to Ashes, hunt the hunter, I know the baron is frightened"
a fairly obvious reference to David Bowie's Ashes to Ashes.
("Ashes to Ashes, Funk to Funky, we know major Tom's a junkie"
And I don't have to mention the "I SEE DEAD PEOPLE", I suppose.
Edit: two more that crept into my mind, both Kurosawa references.
1. When playing a male PC, Fat Larry talks about needing a "Yojimbo" to do a job (Traffik quest). "Yojimbo", Japanese for bodyguard, is a film by Kurosawa about a lone samurai taking out two gangs in a village by playing them of against each other. And in the traffik quest two gangs are involved. (BTW the movie was later adapted as a western by Sergio Leone: "For a fistful of dollars".
2. If you are uncouth to Isaac, he tells you that if the Camarilla will ever come to attack Hollywood they will get a warm welcome and it will look like "an action scene by Kurosawa".