As far as fat, you're going to see the best results from cardiovascular workouts. Remember:
There's no such thing as spot training!
That is to say, there's no way to target the fat in a particular area. You just burn fat, and your body chooses where it disappears from (it's a hormonal thing, possibly coded by your DNA).
You lose fat by requiring and using energy. What is fat? It's just stored energy -- so you tap into these fat store by using more energy that you've eaten (calories) in a day. Your body requires energy, but there's not enough available, so it goes to your fat energy storage and empties the fat cells out.
Doing machines in a gym for particular areas is to increase the muscle in those areas. Bigger muscles require more energy to sustain them, so that's more calories burned in a day. However, because of the way the energy systems of the body work, weightlifting burns carbohydrates more than fat as an energy source.
