[Need answer] Is this keyword is good?

It sounds a bit competitive... but what you really have to look at are the stats for the top 3 results. What is their PR, how many backlinks do they have, is the keyword in the domain name, is the keyword in the URL, etc. If you can build your site up to their level and beyond, you can outrank them.

It sounds like you're looking for some magic bullet that will put you on the #1 position of Google instantly. It doesn't work like that.

You have to optimize your own site. One of the best things you can do is use the keyword in your domain... not in your URL, in your domain name. Use it in your URL, too. In my experience, this helps immensely.

Get relevant backlinks to your site. Build up your PageRank, if you can. It will take time, but if you do make it in the top 3 it should be well worth it.

First and foremost, don't do anything until you thoroughly research your
market.

1. Do they actually spend money?
2. Do they actually spend money?

Secondly, you'll need to know more than is one keyword a good one.

Is that keyword... is it a keyword, as in one word, or is it a phrase? Like
3-4 words in your "keyword."

Also, different keyword phrases reflect different phases of the search
process that reflect the person's intention. But it depends on the purpose
of your site. Basically, if you want to sell something it's good to use keywords
that reflect the person being ready to buy something.

You can optimize for a phrase, but perhaps it's a research type of intention
keyword phrase. No one buys and you wonder why. A little over-simplified, but
that's the general idea.

Also... you'll need more than one kw or kw phrase if you're going to build a site
to rank in the se's. Right?

So, you're a little off in your perspective and approach.

Don't get hung-up too much about PR. It's good that you noticed there are no
authority sites on page 1. But on the other hand there could be a good reason
for that. Have to look at all the angles. The reason could have to do with the
keyword. Maybe not, but maybe so.

The search volume, if you're using G's ext keyword/adwords tool, is not reliable.
Remember that. It can be pretty close, but it also can be pretty off. You have no
way of knowing unless you do something like look at adwords ppc impressions for
a month, then you'll know for sure.

Also... take a look at the ranking url's on page one. Are there any homepages, or
are they all inner pages? You'll rank easier, generally speaking, if they're inner pages.
But that is not the only thing you take into consideration. Just another indicator.

Do market research first, select good keyword phrases based on research which
includes page one serps data, then proceed.

Ken