Answer: You would want to have the highest possible volume to surface area ratio in an ice cube.
When you put ice into your drink, the goal is to have the ice chill your drink. This takes time. Therefore, you would want the ice to slow melt and cool the drink for as long as you can.
If your ice cube is mostly surface area with less volume, it will melts to quickly and water down your drink. If your ice cube has a higher ratio of volume to surface area, it will stay solid longer and chill your drink longer.