I was exactly where you are 18 months ago, so here's some advice from someone who's been there.
We're often told that the way to lose weight is by exercising. It isn't true. Exercise has many excellent benefits, but weight loss isn't one of them. In fact, exercise can make weight loss harder because your body becomes desperate for energy and can make it very difficult for you to not overeat. Two or three hours of hard exercise is cancelled out, in weight loss terms, by a couple of slices of pizza. It's a whole lot easier to just not eat as much pizza.
If your goal is to lose weight, then the answer is simple: consume fewer calories than your body burns. A healthy male burns around 2000 calories a day (depending on metabolism, genetics, etc.). There are about 3500 calories in a pound of body fat. If you reduce your calorie intake to about 1200 calories a day on average, you can expect to lose a couple of pounds a week like clockwork.
This can be improved with moderate (not strenuous) exercise. I lost about 30 pounds in 3 months by eating less and simply walking for about an hour a day.
Don't reduce your calorie intake to starvation levels, or your body's metabolism will shut down and you'll go through a lot of pain with very little to show for it. Also, avoid nutrition-free calories like junk food and soda. Whatever makes up your 1200 or so intake should be dense in nutrition. This is also called "eating healthy." It'll help you to control yourself if your body isn't craving vitamins. A standard multivitamin might also be a good idea.
At some point, you'll get your weight down close to where you want it. That's when you can start workouts designed to increase muscle mass and muscle tone. Until then, keep in mind that very few people are able to lose weight and exercise vigorously at the same time.
It took you years to build up your weight. Don't get discouraged that it takes a few months to lose it. There are no easy fixes in fitness, just consistency, patience, and discipline. The good news is that your body wants to be at a healthy weight; all it needs from you is to give it a chance to heal from years of overeating.
Good luck on your goals!