Legal names and hosting names mean domains that are keyword(s) related to legal or hosting business. Like webhost.com webserver.com dedicated.com etc.
I've uploaded a pretty old list of AdWords per-click rates on almost 50,000 keywords. The data was gathered back in 2005, however this list is still a good source of ideas:
http://www.accomatic.com/Top-Adsense-Keywords.xls
Next, don't overly trust Overture data. The numbers there are from Yahoo and few smaller engines, not from Google that dominates the market; most of the numbers are inflated or skewed because of automated tools checking SERPs. In my experience the information from wordtracker.com and keyworddiscovery.com is much more close to reality.
All the best,
Kate