I would think you'd want a high CRI non-incandescent for color critical work. Yes, incandescent lights have a theoretically perfect CRI, but their color temperature is so low that the light they put out is very blue deficient. Many people apparently like that light and praise it for its warmth, but it's so lacking in blue that it distorts color perception at least as badly as a low CRI would. I'd rather deal with the small imperfections in the light from a 90+ CRI fluorescent or LED with a color temperature of 4000K or 5000K than the lack of blue from a 100 CRI incandescent.

You could always shop specifically for fans that have the kind of socket you want. Despite what you say, there are actually plenty of ceiling fans out there that still use medium base bulbs. You can even buy a fan and the light set separately, so you can get exactly the lights you want. But don't let that get in the way of a rant.

Everything is a continuum.

That is an exaggeration. Things grow as a continuum, but they can get separated when the parts in the middle die off. You wind up with a branched structure because things really can get far enough separated that when the middle dies off they can't reconnect. For example, mammals really are distinct from other tetrapods because the forms that connected them died off and they've been developing in different directions ever since.

oh forget it, this meme is no longer funny.

Nobody else around here lets that kind of thing stop them.

I wonder how much of that is because of the way you're using them. They give a lifespan estimate, but that's making some very broad assumptions about how you use them. Those estimates about how many years they'll last are based on you using it for so many hours per day but only turning it on a few times per day. If you turn the light on and off many times per day, as you might in a bathroom or if you're using an occupancy sensor, the filaments will wear out a lot sooner than the projected lifespan. If you're really turning the lights on and off a lot, LEDs are probably a better choice.

Their energy savings is not that much better than CFLs...

That depends on what you consider "much better". The newer LED bulbs at big box retailers like Home Depot are now using around 1/3 less power than equivalent CFLs. That's not the same kind of savings you get from switching from incandescent to CFL, but it's still substantial. If power costs more than about $0.10/kW, they're probably worth the increased up-front cost.

Sometimes, the cheapest and most efficient LED bulbs are in the blue end of the spectrum, especially when the color temperature doesn't matter too much - like a flashlight.

In that case, it's not so much the color temperature as it is the spectrum. The color temperature tells you what temperature of blackbody radiation your light source most closely resembles, but it doesn't tell you how closely it resembles it. Our eyes work best with light that has a distribution similar to blackbody radiation, i.e. with a wide, smooth distribution of wavelengths. If the distribution has sharp spikes, it can cause things to look the wrong color compared to what they're expected to look like. This is most obvious if you get one of the LED lights that uses a mix of pure red, green, and blue to simulate other colors; you can get something that looks like white if you look directly at the lights, but nothing they shine on looks right. That color shift is what CRI (color rendering index) is supposed to measure.

Lights have to have a CRI of at least 80 to qualify for Energy Star, which means that most household lights are now fairly decent. Cheaper lights and ones not intended for general illumination may go for higher efficiency at the cost of lower CRI, which is what you're probably noticing in the light from flashlights. High CRI (90+) lights are available, but they're usually a bit more expensive and less efficient.

Generally speaking, anything with lots of parts has more points of failures.

Maybe that's true in general, but in the specific case of lighting, incandescent lights obviously have a much shorter life span than CFLs or LEDs. There's plenty of reason to think that incandescent lights do badly with power spikes. My experience is that they're a lot more likely to fail when you turn the light on than any other time, which suggests susceptibility to power surges. It's just that replacing dead incandescent lights is a regular activity, so the occasional failure due to power spikes is much less noticeable than for a light you expect to replace once or twice a decade.

I wouldn't be so sure that energy efficient lights a lot more sensitive to dirty power than incandescent lights. It's just that incandescent lights have such a high background failure rate. If a CFL or LED light dies, you assume there must be a problem with it because their rate of natural death is so low. With incandescent lights, you would have a hard time telling whether one died because of bad power or because it's just given up the ghost.

The extent to which the FDA makes US food crappy is ludicrous.

And you know this because you've read the relevant sections of 21CFR? I actually have, and I can tell you that the FDA does not for the most part force food to be crappy. In many cases it allows food to be crappy by setting standards primarily for safety rather than quality, but most kinds of food can be produced to higher standards than the FDA minimum. There are only a few cases- cheeses aged for less than 60 days and made with unpasteurized milk being the most commonly given example- where the FDA gets in the way, but they're the exception rather than the rule. And, BTW, the FDA is not the relevant authority for meat, which is regulated by USDA.

Whether it makes more sense to have a central DC power supply or to have wall warts depends on details like the relative efficiency of the central power supply vs. wall warts, the voltage and current you're using, and the length of wires. Using a central power supply is only advantageous if it has a substantial efficiency advantage over individual converters. Otherwise the efficiency gains will be eaten up by resistive losses.

The ease of low voltage power is probably better than you think. The systems are supposed to be separated, but that separation doesn't have to be very substantial. They make raceways with two channels so you can have both power and signaling wiring without having to install completely separate raceways. There's also stuff like NM-S cable, which is specifically designed to maintain that separation while making installation easy. And at least under US rules, limited power wiring has much simpler installation requirements; it doesn't need the same degree of protection that power wiring does.

I assume Ovens can do the same?

You should assume no such thing. LEDs have a very serious problem with damage from heat. Fluorescent lights have a similar, though not as severe, problem with heat. Incandescent bulbs, which rely on heat to generate light, are fine with high temperatures. Unless you're going to go with a fiber optic system so the lights are far from where they're used, incandescent lighting is the only practical option for ovens.

How often do you see LED traffic lights with dead pixels, so to speak? I see that all the time.

That's actually by design, at least in part. Burned-out traffic lights are very expensive to replace; the cost of labor and equipment dwarfs the cost of materials. So the LED traffic lights are designed with many individual lights so that they'll burn out gradually rather than suddenly. That gives the maintenance people plenty of advance notice when the light will need replacement. It's a good bet that those lights have also been operating around the clock for many years before they get raggedy the way you describe them; the LEDs have expected service life of many tens of thousands of hours.

The newer Cree 100W equivalent bulbs are a bit bigger than a 100W incandescent (A21 rather than A19), but they'll still fit in most fixtures. And they use 18W for 1600 lumens vs. 26W for most CFLs, which is a substantial improvement in efficiency. You can find smaller ones that are a little bit less efficient from Philips or Feit. These are all available at Home Depot, so it's not as if they're exotic technology. You can get even more efficient ones (albeit at much higher price) if you look on Amazon.

You need to be careful about wiring for DC. Most stuff that uses DC operates at between 5 and 12 volts. If you want to drive something that uses real power, that means a high current and high resistive losses unless you use very big wires. A separate DC power system might make sense if you're going to use higher voltages- which you can do for lighting- but it's a crazy idea for 5V USB power. You'd be much better off getting one of those AC outlets that includes a DC power supply and USB charging sockets.