Actually, yesterday I shot a photograph indoors with a tubelight (on the wall) and a flash on. The results were "too" boring. The flash had robbed away all the natural looks of the scene.
Does using normal light bulbs as compared to flash show some difference in the outputs?
Maybe, but usually not. House lights have several disadvantages.
First and most importantly, the light from a flash is significantly brighter for its short duration. This allows you to use lower, less-noisy ISO settings and narrower apertures. The short burst of the flash pulse itself can also freeze motion better than a shutter, which is nice for sharpness.
In order to get the same level of output from an incandescent or fluorescent bulb, you'll need a lot of power — more than normal house lights, so you're in to making (or buying) a special setup of some sort. And if you're doing that, there are many special setups you can do using a flash as well.
That power, in turn, can be very hot, if you're using incandescent lights, which is not so good for your subject. Alternately, if you're using fluorescent tubes, you may have unpleasant color rendering issues to deal with. And the bright, constant light can make people's eyes contract so the pupils are tiny spots, which isn't what one always wants.
Sometimes, when you're going for a naturalistic, documentary look, artificial light can be a deal-breaker. But for many shots, it's very beneficial to modify the light in some way, even with just a reflector. Having a constant source of light makes it easier to see in advance how the light falls (and reflects) without taking test shots (or using the "model light" strobe feature of some flashes).
But, mostly, what you want to do is:
You should also experiment with balancing the flash output with the light that's already there — artificial indoor light or sunlight. That gives you a lot of creative control.
Also, if you want to shoot decent pictures indoors without a flash, you really want a lens with a wide aperture. This typically means fixed focal length — zoom lenses have more complicated and bulky mechanics that get in the way of just plain pulling in as much light through the lens as possible.
Try to get at least f/1.4, but if you can find a good and affordable f/1.2 or even f/1.0 (unlikely, I know) lens for your camera, go for it. I picked up a Sigma 30mm F1.4 EX DC HSM at a good price for my Nikon D70s some years ago, and I've been happy with it, but please don't consider this a professional review in any sense. My point is simply that it's amazing what a difference those few f-stops can make if you haven't tried it.
Of course, wide apertures come with their own disadvantages, chief among them being narrow depth of field. On the other hand, you can also use this to your advantage — a narrow DoF will blur out distracting background clutter (which is common indoors), and thereby help bring out the subject.
The ambient light sometimes retains the specific mood of the surroundings. For instance, in a restaurant or a club the lights are arranged to create the mood. Firing flash in such scenarios definitely disrupts the mood that otherwise would have been nicely captured in the image.
When in low light, a tripod serves the purpose and the image can be captured in available indoor light.
To add to the previous post on mixing flash with ambient light - you will usually need to add gel filters to a flashgun to match its color to ambient light. There are standard ones with a greenish tint for fluorescent lights and an orange tint for incandescent lights. Otherwise. And of course your white balance camera setting (if taking jpeg photographs) will have to adjusted to match.
