Just ran across the domain Logo.com for sale on Sedo with an asking price of $1,500,000. The auction states that the domain gets over 1,500 visits potential customers per day. Using these keyword research tools according to Google the keyword logo gets searched for over 45,000,000 times/month broad match and 1,000,000 times/month exact match. The longtail for key phrases with logo in them is absolutely huge, the domain is also PageRank 5 and has been registered since 1995.