LED lighting is near and dear to my heart, I'll admit, because I knew graduate students when I was in the PhD program at UC Santa Barbara who were working on the materials science behind blue LASERs and white-light LEDs. The physics and manufacturing of these devices was my specialty, but I still find them magical. A tiny chip a millimeter on a side can convert electric power nearly 100% efficiently into light! It's amazing, even though I understand how it works.
LEDs are nearly 100% efficient, which means that they generate almost no waste heat, and use much less electric power to illuminate a room, so they are far superior in both respects to incandescent lightbulbs. I remember sweating under my desk lamp when I was studying in school in a warm climate, but LEDs produce only light, not heat. They have none of the downsides of fluorescent lights, either -- no flicker, no weird greenish color, no buzz, no blink, no delay in coming on. And they are far more efficient than fluorescent bulbs, while being no more expensive.
One of my favorite features of LED lights is the ability to select the color temperature of the light. In most situations I prefer 4000K light, which is the pure white used in art galleries, to the yellow glow of 3000-3500K bulbs, or the blue cast of 5000K "daylight" LEDs. 4000K LED spotlights make my art "pop," under-cabinet task lights make my food appetizing, bulbs in my closet don't alter the color of my clothing while I'm choosing what to wear, the downlight over the bathroom vanity is flattering to my face, and a track light picks out the controls on the washer in the laundry room. With LED bulbs, I can select the same color temperature for the various fixtures in a room so that everything looks clean and uniformly lit. And, if I'd like to have several moods to choose from, I can strategically place a romantic 3500K bulb in a bedroom lamp, along with 4000K in the closet and reading light.
Did I mention LEDs are cool? I'm a fan!
Our house was outfitted with all fluorescent lights when we bought it, because that was the most efficient technology at the time it was built. The fluorescent bulbs cast ugly greenish light, flickered, and used 3 times more energy than LEDs would to produce the same amount of light. So I set about replacing all the fluorescent light fixtures with LEDs. The previous owner had installed electrical wiring above all the windows, with fluorescent fixtures in wooden shadow boxes that illuminated the cathedral ceiling. We removed the wood and the fluorescent fixtures, took them to the building resale depot, and replaced them with simple metal LED fixtures that use less than 1/3 the power. Each LED light bulb in our house uses between 4 and 9 W. We can turn them all on and be using less than the power one incandescent reading lamp required in my childhood home. We refitted the entire house for less than $1000. And the bulbs will last many years longer than incandescent or fluorescent bulbs would, for no more cost.
We also installed solar-powered metal LED landscape lights that shed a soft downward glow on the path from our car to our door, and a solar-powered LED motion-sensor light above our grill. They were inexpensive, simple to install, are fully automatic, and require no power from our house system.