Here are some more tips on choosing the best domain name:
1) Don't register domain names that are too long and have too many syllables if you can help it. Yes, you can register names up to 63 characters long, but that doesn't mean you have to use all 63 characters.
You want your name to be easy to remember. Not everyone will bookmark your page initially so try to think of something that can be easily remembered -- although I realize this may be tricky since a lot of names are taken these days.
2) Use hyphens if your name is more than 3 words long (unless your name includes 3 short words). A name like carbuying.com doesn't really need a hyphen because it's readable the way it is.
However a name like used-car-buying-scams.com looks better than usedcarbuyingscams.com since there are so many words in the name.
3) Protect your name by registering multiple extensions (.net, .org, etc.) This deters people from copying your name. For example, if you own garden-tips-for-us.com you can also register garden-tips-for-us.net and any other extension that's available.
You don't have to build a site on all the domains, but you can reserve the others to keep people (copycats) from registering them.