The 'Kirby Plaza' is actually the City National Plaza in Los Angeles. The red stair step art piece in the fountain is "Double Ascention" and has been a favorite piece of public art since 1973.
Ellen Greene (Sylar's mother, Virginia Grey) gives a subtle but clear nod to fans when she says "I hear it's beautiful there; green everywhere" as she grasps the Oregon snow globe using the same gesture she uses when singing "Somewhere That's Green" in Little Shop of Horrors (1986).