Not withstanding much experience with AdWords. It would seem logical to me to say "it depends".
First make sure that you are ready for AdWords. Do you have a system in place that allows you to track the traffic and how it is converted into sales. At the end of the day you want the keywords and the ads that work to make you money not just bring you traffic.
With that in place, I would look at the natural searches that come into your website and convert to business. List their frequency and pick the onces that obviously build a cluster. You usually see a few build the bulk of your referrals from search engines.
These are the keywords that I'd start with and see how effective they are. Once you have the mechanics down to track your data and know what is really profitable, I'd go and set aside a budget as percentage of sales to try new keywords and expand the universe. What works stays and what does not work goes.
Just my two thoughts.
K<o>
|