Many marketing and advertising costs are recurring. Re-registering domain names is a minimal cost, but many domains (especially .com names) get type in traffic worth thousands of dollars a year. Some get type in traffic worth thousands per day. And this traffic stream is defensible from search engine algorithmic swings.
In addition to the defensibility issue, there is a large synergy between great domain names and SEO. Domain names containing your keywords as part of the name make it easier to get your keywords in the anchor text when people reference your company by its official name. This is true even if the domain has hyphens and/or additional words. But domains with hyphens in them are harder to market than domains without hyphens.
Exact match domains make people more likely to give you targeted anchor text when they mention your website. In some cases a strong domain name also makes a site appear more trustworthy and linkworthy.
Google recently increased their number of sitelinks to 8 and now list them in a 2 column format. To visualize the value of this, consider that I have a decent sized monitor and only 1 listing not controlled by me appears above the fold when searching for SEO Book.
And look at a search for credit cards
In time I have to expect that for high value keywords (as per AdWords advertiser stats) Google will manually review generic matching names with sitelinks to determine if they are brand oriented or not. If the sites with sitelinks for high value queries are not strong brand oriented sites, is Google going to keep giving this much exposure to whoever owns the exact match domain?
Using Organic Search Profits to Fund Ad Budgets that Lock Out Competing Sites
If the results stay like they are right now, Google is creating a dominate player that will likely overspend on the associated AdWords ads to further block out competition.
Who cares if you lose a few bucks on the ads if it further increases your volume to get you better payouts AND reinforces your default status as THE market leader? Plus, exact match domains consistently get a higher CTR than non-matching domains, so in that regard the domain name not only ensures the sitemap in the search results but also subsidizes the AdWords ad costs.
Domain Names Win Fatter Margins in the Game of Arbitrage
If, after seeing the above images, you still don't appreciate the value of domain names in search marketing, please give Frank Schilling's post on arbitrage titled The House Always Wins a read, then go on a domain buying binge.
Life isn't fair, but that doesn't mean that you should ignore the obvious deals! If you are a diverse publisher and domain names are not part of your SEO strategy, then hopefully you can correct that deficiency before the year is out.
Some of my domain names were registered as a joke (haggisdiet.com was a bet against Andy Hagans), and it wouldn't be hard to register domains in the name of another person. Having said that, I doubt few people put my name on their domain names, and now you can look up a list of domains owned by a person by using Registrant Search. If you have thin affiliate sites that rank well in Google and are not using fake whois data then now might be a little late to start.
Via Domain Name News I recently discovered Sold Names, which aggregates publicly available price data for domain sales. You can also view last week's sales at DN Journal. If you find someone underselling a domain name browse through their inventory and see if they have any others worth buying.
In a world dominated by .coms an ad agency decided to promote a financial services company as being different by highlighting the .org in their name to show their non commercial / non-profit nature. 99 times out of 100 a .com is better than a .org, but if you can get a name that costs a million for the .com and only pay a few grand for the .org version and then add $998,000 of marketing to it I think the .org comes out on top.
Using a .org can also make your business look more trustworthy if you are offering a free service and/or are a quasi non-profit. A large part of the current price differential between .com, .net, and .org names is that those who are the biggest domain buyers do not have much development talent or intent to develop them. As a PPC lander page it is hard to earn much as a .net or .org.