I am looking to grow no more than three plants and I am considering using LEDs, how many watts per plant will suffice?
Growing any plant isn't about the wattage of the setup, but the lumens produced thereof. With LED's this is especially true, since the light is much more efficiently produced from electricity. A buddy of mine has 10 plants sitting under three 60watt LED panels, where each LED is producing .3 watts. From this setup, 18watts per plant if you evenly disperse the diodes on a panel. I think you might get the best result if you mounted the diodes on a curved mylar plated panel, but I haven't tested this.