Any type of aerobic movement is better than nothing, but it's best to select activities that cause you to support all or most of your own body weight. Why? This challenges your body and helps to increase your metabolism, which causes you to burns more calories and ultimately lose more weight.
What you choose depends on your personal interest, schedule, and current fitness level, but the good news is there's a lot to choose from. Bob's advice—choose two that you perform regularly and a few alternate ones to spice up your workouts when those feel too routine.