Out of the many machines in the gym, the elliptical I find is one of the best for full body training and weight loss. They are easy on your joints, and most are very ergonomic efficient and easy to use.
Elliptical Machines work your whole body. The work your quadriceps, hamstrings, gluets, and calves. Elliptical's also work the upper body. This in combination with upper and lower body in turn will burn more calories and therefore help cause you burn more calories and lose more weight. So go ahead and jump on an elliptical.
Below is a simple interval workout that will also help you burn more calories while on the elliptical.