I have experience with "Coffee." Go local. Compare the cost to targeted direct mail. Skip content delivery entirely. Track confirmation of submitted forms, but assume at least as much call volume than forms in most cases. G has been best. Focus landing pages with "local expert" appeal. Major selling point IMHO.
What bigjohnt said, but I'd also add that tracking online leads and conversions is not enough. If you're going to be advertising on as large a keyword set as you should (I'd say 10K-50K keywords for the legal sector alone), then you'll need to automate the process of feeding the conversion data along with the impression/click/cost data into a system that can understand cost, revenue and profit for all keywords and then automate bid management for all keywords on the SE's you're participating in.
There are a number of firms providing keyword management systems:
Efficient Frontier (where I work) AtlasOnePoint Did-It KeywordMax PPCPro BidBuddy (UK) Latitude (UK)
NOTE: if you're going to be spending a significant amount on Google, realize that it's an opaque environment where the system you use needs to be able to *accurately* model how changes in your max CPC will affect impressions, clicks and conversions. Google's Traffic Estimator doesn't work (it estimates traffic based on an average of all advertisers, & not based on how your own specific campaign performs). As far as I know, there's only one keyword management system (: that can do that.