Taito garnered a reputation for working magic on the NES, and their port of Arkanoid is the perfect example. While there are subtle differences in the lay-out of each level, the game itself, with all of its graphics, sound and game play, is practically carbon-copied from the arcade. However, there is little chance of appreciating the similarities if Arkanoid is played using the NES's standard controllers; the game really needs analog control to keep up with the speed. Taito, much to their credit, offered support for analog controllers like paddles and mice when porting Arkanoid to other systems, but the NES didn't have any such controller at the time. So, Taito created one, and bundled it with the game. This controller makes all the difference in the world, turning NES Arkanoid into a first-class translation.
This one is highly recommended, but definitely make sure you get the controller too.