I keep saying this but rest & relaxation are an important component of a healthy lifestyle - just as important for body and mind, as the exercise itself. You could exercise daily, as long as you vary the type of exercise, and the focus of the exercise. But as part of a long term plan that will keep you fit beyond weight loss, consider doing three to four fairly intense workouts per week, each lasting no more than one hour. These workouts might be running, gym cardio, weight lifting or mixed. Variety is the spice of life. Allow some days off from any rigorous exercise, to both allow muscles to repair, and to have some fun.
On top of that, try to increase general activity daily - how far you walk, how many stairs that you climb, going for after meal walks etc. A pedometer is a handy and cheap tool to gauge how active you are, and to track your progress.
If weight loss is to be long term, then your plan of action should be a long term lifestyle change.