June's top domain categories (most searched groupings) on Afternic: 1. Business 2. Financial 3. Health 4. Computers 5. Sports
Go and have a look at what is selling at sedo now. You will find just about all types of domain names.
Any domain name that can gathers others brains attention for a larger period of time than average domains, also dictionary words, and of course if Trade mark is not broken, big companies related domain names. For example: good-loans-for-people.biz is not that strong as bestloans.com or thebestloans.com or betterloans.com I guess you got the idea, 1st domain maybe is worth just the 8 usd it cost or less lol, but the next three maybe worth thousands and if sold to the right Company a lot more. Regards Maurice