it doesnt help if you are #1 on google for a term which isn't searched.
you therefore need to find out, what terms people are searching for.
in the example of "home rate", #1 search term is "home equity loan rate".
if your site is on #1 on google with this term, you would get a good amount of traffic. beeing #1 for the term "australia" would bring more visitors to your site then beeing #1 for the term "syria" – because of the larger market / more searches. but as better the keyword gets, as more competition you will face to get on the first page of google-results. ideally you have to find keywords with high seach volume and little competition (almost impossible).
seach engine positioning always relates to a keyword. in the end, the only thing that matters is how many visitors you get from which keywords. if you want to make a travel site for people traveling to australia, you have to rank high in "your" search terms. if you are on the first results page for australia, hotels in australia, flights to australia and so on, then you will get lots of targeted visitors to your site. it wouldn't help to be #1 for syria, if you want to offer hotels in australia.
beside of that, you have to consider the "value" of the term itself. 1.000 visitors looking for a loan are "worth more" than 10.000 visitors looking for free web design templates.
a keyword domain will help you in terms of ranking. but especially in valuable fields like loan, porn or gambling with high competition, it is only a small part of the whole
seo-process.
regarding hypens:
seo-wise it shouldn't make much difference.
the tools i use are:
yahoo overture
google traffic estiminator
google keyword tool
google trends
all these tools give you some information you will need to find better keywords. but there are also other tools like wordtracker, etc..
the list i posted is from overture, but keep in mind that ovt doesnt distinguish between singular and plural – for this you have to use common sense.
hope i could help and sorry for my bad english
