My preference is elliptical crosstrainer, either Precor (without arms) or Lifefiteness (with arms). The former I prefer. 4 -5 days 15 minutes, with varying intensity levels and inclines. Then do some light weight training also. Try to increase your cardio 5 minutes per week, until you can do 45 minutes. Be sure to drink a ton of water, some before, alot during, and alot after, to avoid dehydration and cramping. Be sure to stretch after. Be sure to warm up for 3 -5 minutes on the apparatus, and cool down on the apparatus. Force yourself to sprint after a few sessions of this. Also, make sure you do some resistance climbing on these machine.

After a couple of months of elliptical training, try to find a spinning class in your gym. I takes the boredom out of cardio because you're in a class and being instructed on form. Also, the music will motivate you. I always have a meal replacement shake post-workout.

The reason I suggest weight training in addition to the cardio is you will burn muscle if you only do cardio. Also, muscle helps to burn fat.

As far as fat burners. I don't recommend them right away, but that's up to you. Since I lost all my weight, I cycle on and off of them depending on my cycle.

The most important thing is your food. Try to eat clean: chicken, turkey, lean steak, vegetables, complex carbohydrates, which contrary to some people's belief's are necessary for endurance, and energy. You need them to hold on to some of your muscle also.

Also, 6 small meals a day will speed up your metabolic rate much more than 3 meals a day. It's more imporant to try to keep your metabolism burning at a fairly even level. With only three meals a day your body goes into starvation mode, and you lose energy in between meals. With this type of eating, you don't really need thermogenics or fat-burners because your body will do it automatically if you're working out. Also, if you do decide to try fat-burners do not exceed the recommended doses.
Ephedrine is addicting, and eventually it stops working if you use it for too long. Then you have to keep increasing your dose. They all work pretty well. They make you sweat like crazy, so you have to drink tons of water with them, or you'll dehydrate and cramp and lose muscle.

Best bet is to take 2 days off for recovery. Many people take weekends off, and you'll be energized for the upcoming week. Eventually, when you lose the weight and fat you want, you'll need to probably cut down to 3 days cardio and 3 days weights, on separate days, and start some serious resistance training, but that's getting way ahead.