Early on I bought airline-tickets-cheap.info. Put a two page site on it with tips on buying cheap tickets and international travel in general.
All major extensions were taken, really great keywords.
After a year it was getting about three uniques per month. Maybe two hyphens are search engine poison as some people said, maybe it was too long, whatever. I moved the site to CTIK.com, droped the original name, and it now is growing nicely.
My rule, in light of the above - develop names that I would want to own as a domain investment.