All of them are great and burn calories, you burn more the higher the intensity and the longer the activity. they do have different exercise values, but off the top of my head it's either running or elliptical that burns the most. it also depends on how much you weigh. for example if you do the elliptical and it has a METS value of 8, you multiply 8 x your weight kg and will come up with how many calories are burned in an hour. then it's a matter of working out how long you exercised for, and thats your answer.
do whichever one you enjoy the most, or mix up your routine by doing a different one on the days you exercise. you need to keep it interesting and enjoyable.
basically you need to get a thing called the METS values which show you the values of different exercises of different intensities. that will give you your answer.