twenty-first floor of the Chiba Hilton. There is, in fact, a Hilton in present-day Chiba, outside Tokyo. It does not, however, have twenty-one or more floors. It’s perhaps, reassuring to the reader that the Hilton chain still exists. In fact, many name brands are still present in Gibson’s book.
white Braun coffeemaker. Also exists:

(amazon.com)
Also, the drinking of coffee relates the world once again to our own; it’s conceivable that an octagon could serve the same function as caffeine, but the coffee is more accessible.
imitation ricepaper. An excellent example of a combination of the two halves of the novel’s cultural references—ricepaper is recognizable, imitation ricepaper is a little stranger.
(www1.hilton.com)
jockey. A reference to the person who rides a horse in a race, here applied to something else: someone who uses a computer deck for hacking-type excursions. Similar to “coffin.”