Friends - A little caveot here. I'm just a Humble Newb who will be asking more questions than I contribute. After Enjoying some of the features of Gravel I went looking for more examples of what to do with it. I discovered that I already knew most of what everyone else posted about but I'll still list some of them here. After that, I'll share a few other ideas that many of you probably already realize.

1) Fill in water or lava ponds or falls. - Nice because the gravel sinks to the bottom. The area can be filled completely then the gravel removed along with any trace of the lava or water. The same can be done with sand but since glass blocks are really cool building blocks, I save the sand for constructions.

2) You have a chance to get flint from the gravel.

3) Cheap undesireable material to even out the shallow holes in caves when you don't want to waste any of your other materials.

4) As an alternative building material to provide a different texture especially for gravel roads. Hey, whatever makes you happy! 

5) Some indicated that it could be used to build a fountain where the water just appears out of thin air. This is because the blocks will just drop away from the water and leave it in place. I haven't tested that yet but it sounds good to me.

Then I went to the Nether and things changed. My portal ended up high above a lava lake in the Nether on a small platform about 45 blocks high. I first built a Bridge of Cobblestone to get me above solid ground then found a way to get to the ground without jumping to my death. 

6) Ground up Scaffolding. Attach the gravel to the side of a high platform. Since the gravel obeys gravity, it falls. Add another and it falls to stack on top of the previous. Keep adding until the stack reaches you. Step onto it then dig your way down.
 
7) Ground down Scaffolding. As a natural inverse to creating a tower from height, the scaffold can be removed from the bottom. This is without having to build a side tower and then demolish both of them from the top down.

8) Fast Demolition. Using a shovel removes gravel scaffold blocks fast.

There it is. Why use Gravel? Because you usually have too much of it and you don't want to use your good stuff  for temporary work.

Other Ideas? Refinements? Anecdotes? Let's see them!

Mark