Barbells Rule
I can't speak highly enough about learning how to train with a barbell.
It is the single most effective and versatile piece of equipment for increasing fitness. Everyone should learn how to use it at a young age so they have the tools they need to stay fit throughout their lives.
Light and Fast
Traditionally a barbell is thought of for lifting progressively heavy weight, and it sure is good at that, but there is a lot of benefit to moving lighter loads quickly. The effect of lifting lighter weights quickly is almost identical to that of traditional "cardio" on the heart and lungs. Additionally, with barbell training, you get the benefit of a full range of motion and increased muscle recruitment. Basically, I'm saying that you get all the benefits of "cardio" plus building muscle at the same time.
Power
Strength expressed with speed is power, and it's hard to get really powerful without moving heavy loads quickly. This can be achieved with ballistic gymnastic movements like tumbling, but most people don't have access to adequate space in their gym to do that sort of thing, nor do they have the patience to learn and practice those difficult things. However, I must be sure to say that I see great value in learning new things and developing the ability to control your body like a gymnast if you have the time and resources to do so.
For most people, the barbell provides a sufficient avenue for increasing power. Training using the Olympic lifts (snatch and, clean and jerk) or even a modified version of these lifts from the hang position can do great things for your power and speed development.
Strength
The barbell is the method of training for the world's strongest people. It is unrivaled in developing pure strength. While at the upper level of competitive strength sports, there are many other tools used to push their bodies to the absolute max, the majority of their training is performed with a barbell. Even if your goal is not to be that strong, it's okay to admit that it would be nice to be a little bit stronger. That couldn't hurt, right?
Developing a basic and functional knowledge of the most effective lifts and how to put them together in a training plan is beneficial for anyone wanting to improve their fitness. For those people who like to go to the gym and glide on the elliptical for 30 minutes every day, if they were to mix in barbell training 2 days a week instead, the change in their fitness would be incredible. For those people who do some resistance training but use machines, the impact of barbell training on their athleticism and overall strength can not be understated.
I know that barbells can seem intimidating to some, but we're often afraid of what we don't understand. Take the time to learn how to use a barbell well and you'll have the skills you need to maintain lifelong fitness.