The equipment required to build up your body really depends on how extreme you want to get. If you plan on getting competition worthy, you will need a wide range of free weights and machines to work out all the different parts of your body from all angles. The trick to building a lot of muscle, is not necessarily heavy weights, after all, you don't want to injure yourself. You can start off with a moderate weight, just do a lot of repetitions.
I think that free weights are essential. Lifting barbells and dumbbells (at varying weights) is a great way to build muscle evenly over your whole body. Also getting a bench and squat rack would be very helpful. Remember that you need to gradually increase the amount of weight that you are lifting and change exercises occasionally so your body doesn't get used to the routine. Start off slow and at a reasonable weight to stay safe. You can usually purchase bars with a wide range of plates from a sporting goods store. In some places, you may be able to find as much as a 300-pound set. Just check around and see what you can find in your area. When you use barbells, always make sure that you have a spotter, just in case. I am overly cautious when I work out, no matter what I am doing, and often have a friend accompany me to the gym.
Using a chin up bar is an easy, and space saving way, to build your upper body. I often use a pull down machine to work out my back as well. It is a very versatile piece of equipment and can do several different upper body workouts. I would also recommend that you work out your legs as well. Doing squats, leg extensions and leg curls can really do wonders. Also, try to work in some weighted leg presses and lunges. They are an easy way to keep your legs ripped.
Also make sure that you have some way to do a cardio workout. Cardio not only builds endurance, but also burns fat. Even though your need to work at a slower pace, it is still essential to bodybuilding to help you along your way. As you burn more fat, you will see your muscle definition more prominently.