Guinea pigs and rabbits both make suitable pets. Although a guinea pig is content being in his cage with his buddies until playtime, rabbits are more like cats and dogs, and they like to be out whenever possible.
If you have smaller children, a guinea pig offers the advantage of being awake during the day. However, small children might bond better with rabbits.
Weigh the pros and cons before deciding which pet to pick. The answer really depends on what your family is looking for.