I do agree with you on branding. But imagine how many people type in casino.com into the url bar.
I get several hits a week from people who type in casino.com into a search engine and for some reason they find my website. Combine this with how much easier it is to get listed high in the search engines.
If i had 5 million to invest or even 1 million i certainly would not waste it on a domain name. But a good name simplifies branding. Remember when overture.com had the domain name goto.com? Or disney had the go.com search engine? Those are a lot easier to brand than gotosearch.com
Then again winneronline and yahoo are two examples of good branding without the expensive domain names.
Antoine