Exercise: is it worth it?

Every day I wake up and all I want is to get 30 minutes of exercise in. And on most days, I do it. But the weight stays the same. Some months I loose inches on the top and gain on the bottom. Some times it's the other way around. The question begs asking: is it worth it?
The answer is obviously YES. When you exercise you are helping your body in many ways. Your bones get stronger, your muscles shape up. Your heart gets stronger, your lungs get cleaner. You have to remember I use to smoke. It takes seven years for your lungs to clean all that crap. I want to cut that in half. I have my work cut out for myself.
Do what you feel comfortable doing, and if you try something new, share it with us.
Keep trying.