Now, a lot of times these great domains that have pending delete will get snapped up in a flash. Okay? You want to use the same system that’s 500,000 domains so you can always sort them by whatever you want to do to make sure you’re only looking at quality domains and look at the link profile the same way. Once you find one that you like, you can’t just sit on your computer at Go Daddy and wait for it drop on 6/14 and expect to get it because there’s going to be a lot of other people gunning for that domain. You actually have to use a service like Snap Name.
As .COM is the natural domain extension for the United States based websites, it does get some priority in the Google.com’s search engine results (based on Google’s US datacenters) when competing against other countries’ domain extensions like .CO.UK, .CO.ZA, .COM.AU etc. However, .COMs don’t get automatic priority over other similar extensions like .ORG, .NET etc. that are also commonly used in the United States. All these domain extensions compete with .COMs on a level playing field.
The second option requires a bit more time and effort than a 301 redirect. You could do a mini overhaul of the site and turn it into a microsite for your main domain. This option is good for exact-match domains for your targeted keyword, and there are other reasons for going the microsite route that Rand's highlighted in his post about root domains, subdomains, subfolders and microsites. This strategy also works better if the old domain has decent rankings for the keywords you're targeting.
If you buy keyword specific domains, you're really buying the type in traffic. I use the URL builder and redirect through that URL so you can see how much traffic your getting from the keyword domain. There seems to be no rythme or reason to what keyword domains deliver traffic and what don't. By tracking traffic with the Google URL builder you get a feel for what names are giving you traffic and which are not. ie. the plural, the singular, two words, three words, the possessive, etc.
So how do you develop that instinct? NameBio maintains a database of over 500,000 historical domain sales (as of writing this post). They have interesting filtering features by which you can narrow down domains by price range, date sold, keywords and more. Simply sifting through the listings on NameBio long enough will quickly develop your domain appraisal “instinct”.