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:
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.