Learn English – Difference between laughing (gerund) and laughter(noun)

Ditto Matt, but maybe it will help if I say it a slightly different way.

"Laughter" is a mass noun, referring to the concept of laughing in general. "Laugh" is a countable noun. A person could let out one laugh or two laughs, but he couldn't make one laughter. On the other hand you could say, "Laughter is not appropriate at a funeral." You are referring to the idea in general. You wouldn't say, "Laugh is not appropriate at a funeral." You might say, "A laugh is not appropriate", though that would be awkward, because you really are talking about the general idea.

It's like the difference between "humanity" (in the sense of the sum total of all human beings) versus "person". You could say, "Humanity is becoming too dependent on technology", meaning all people, in general. Or you could say, "This person is becoming too dependent on technology", meaning one particular person. You wouldn't say, "A humanity is ..." doing whatever, as that would imply that there are other "humanities" out there somewhere.

The government has spent a great deal of money attempting to help the region.

is the best sounding choice to me. Probably context has a lot to do with it.
For example, big is better here:

I don't really care about failing the exam. It's no big deal, really.

And the last example (including a different grammar correction):

It was time for her to make the big decision. Should she agree to marry him?

or

It was time for her to make the big decision should she agree to marry him.

But in another context:

You made a lot of money. That was a great decision.

In these kinds of examples, great refers to something very positive or beneficial (or very negative or disasterous), while "big" has more to do with the importance of something (as in the marriage decision).