Lava, while potentially more dangerous, might be a better option as it more easily occupies a larger volume.
It will be easier to see several bright blocks rather than just one or two.
You could build a glass box on top of a tower and fill it with lava.
This should be visible from afar and relatively safe.
gaming.stackexchange.com/users/13/ChrisF
As of Minecraft 1.4.2, beacons were added, pillars of light that produce a buff when close to it.
For materials: The beacon block itself is made of 5 glass, a Nether Star, and 3 obsidian.
From the wiki: The beam of light is visible from up to 256 blocks away, and is even visible in unloaded chunks.
This provides a useful marker for short to mid-range gameplay.
Here is an image from Jeb:
gaming.stackexchange.com/users/18916/korrasaur
Light in minecraft is pretty limited.
In fact, a light source don't really produce light, it just brighten the cubes around it.
So, a torch on top of a pillar, seen from far away, will just be a white pixel in the sky, not much different from a star.
The best way to see something from far, so, is not to make is bright, it is to make it large and recognizable, something that will not confound itself with the background.
Making a huge ball of glass filled with lava, for example, is a good way to mark a place.
But so is a sphere of red wool covered in torches and a large cube of glowstone.
The difference is brightness from torches vs. lava is negligible for something like this.
For afar, most details will not be visible, but it will still catch the eye as something very different and not natural.
So, in short, to mark a place, make something big and recognizable, not a small, bright light.
gaming.stackexchange.com/users/11089/Jupotter
According to the wiki page your could put Jack O Lantern or Glowstone which are safest and the brightest.
Edit
For the other question that you added, no you can't change the lightning effect since the max value is 15 and the list in the wiki link above shows it.
You could hack the minecraft.jar files for better lightning maybe, but only you will have the effect of that change.
gaming.stackexchange.com/users/11188/Warface
Lighting in Minecraft only goes up to 15, and those light-sources only light up to 15 away.
If I wanted to make something very visible and cheap, I'd go with lava as you can get tons of lava blocks out of one bucketful if you let it run down aways, like this:
gaming.stackexchange.com/users/2259/Nick T
Make a large flat face into a hill with stepped blocks all around.
Make a hollow glass cross form and fill it with lava.
Then remove your scaffolding.
There will be no mistaking it for stars or landscape.
gaming.stackexchange.com/users/32043/gtomlinson
For mods to give more light, Factorization has the Wrathlamp , light traves 8 blocks out to the side before it starts to dim and it travels 27 blocks down before it starts dimming.
If you have high ceilings you can put them at the top of your room and it can light your entire room.
gaming.stackexchange.com/users/3638/Scott Chamberlain
I'm trying to make a beacon/lighthouse which is visible from a distance at night (on far render). What is the best light source which will provide the brightest light / most visible to the human eye when wandering back home at night?   Lava  Torch  Redstone Torch  Glowstone  Netherrack Fire  Other?   Edit: Alternatively, are there any working mods/plugins that produce better lighting alternatives?
How can I make an extremely bright light?
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gaming.stackexchange.com/questions/28828
gaming.stackexchange.com/users/11804/waterwizard11
Certain children that are essential to the quest are not killable. There is a variety of solutions connected to the use of lava or glass, although no mods could be useful.
An extremely bright light can  be created building a big object using materials such as glass, lava or beacon. There are not mods available that that can produce a brighter light.