STUCK IN A CAB ON FIFTH AVE, NEW YORK — New York cabbies don't like change, unless it's the kind you tell them to keep. Nevertheless, if you hit New York for the holidays this year, you might find yourself in a cab with a computer display installed in the barrier between you and the driver. It's not very useful, featuring a little local TV, Zagat ratings and a lot of advertisements. But some of you out there might find they're good for a perverse pleasure. Hacking around. That's the stuck-in-traffic entertainment blogger Billy Chasen went for.