Q: since the leg and arm muscles combined has much more muscle than the ab muscles wont weightrainig the arms and legs be much more beneficial in burning the fat around the stomach area versus just doing stomach exercises and ab exercises?

A: Yes, you're mostly correct. Muscle mass in your body is distributed roughly like this: legs and back (including upper back and traps) have the most muscle by far, then chest and abs, and finally shoulders and arms typically have the least muscle mass. In order to maximize the benefits of weight training you should most certainly train as many different muscles as possible. So as you said, to burn stomach fat (or any other area of fat) most efficiently you should train your whole body. Doing hundreds of crunches will strengthen your abs but it will not burn the fat on the stomach nearly as fast as a whole-body routine.

If you look at the training routines I give in the weightlifting article they all work all the major muscle groups and will probably hit 80-90% of your entire muscle mass. And by emphasizing free-weight training (as opposed to machines) they will also train all the little stabilizer and assist muscles that don't get proper workout with machine equipment.