Be aware that the SEO game has changed a lot since the article at SEOBook was written. Google has started their "anti-EMD" campaign. EMD is "Exact Match Domain", and it was used heavily by spammers. Things like "buy-a-car-with-no-credit.com" and variations without the dashes are now frowned upon by Google.
In picking your domain name, just make sure it's either relevant, or quite simply just make it your business name. You can out rank ANYONE for ANYTHING if you do correct SEO. It doesn't matter whether your domain is "123d32s3s33.com" or "planetfitness.com", as long as you have quality content, you can rank for your domain.
Basic advise on domains is not to make them too long however, unless all you're looking to do is have people click to it from somewhere else. If you want it even remotely memorable, then you should follow the "short but sweet" mentality.