As a Texan who moved to New York City a few years back, I was surprised to find good BBQ here and it's only gotten better.

NYC:
Best Brisket - Hill Country BBQ
Best Beef Ribs - Tie: Daisy Mays & Blue Smoke
Best Pork Ribs - Dinosaur BBQ
Best Sides - Tie: Daisy Mays & Blue Smoke

A few others are decent (RUB & Fette Sau in Brooklyn), but I got to the above mentioned fairly often.