I used to think nothing was better than the elliptical for burning calories, but i was WRONG!
There is a machine at my gym called the tread climber. Its basically a treadmill with the belt platform area split in 2 that will move up and down as your walking. Its supposed to resemble hiking.
In 20 minutes yesterday I did 9/10th of a mile and burned 203 calories! I was sweating thats for sure.
The only down fall is it doesnt work upper body like ellipitical does but with the platforms going up and down I have to keep my hands on the bar at all times or I get off balance.