I'd say it depends on which keywords were leading to more sales. I don't think it's one or the other. A better way to look at it is to set up your keywords and really measure how they perform. Not just the CTR and the cost per click, but how much money you make from each keyword.
As you identify keywords that lead to a positive ROI put more into them and as you find keywords that lead to a negative ROI stop using them unless you're bidding on the words for a reason other than the return.
It's not really about low paying or high paying keywords, but about finding keywords that make you money.
Very specific keywords convert the best. Try getting on the first page, people usually visit you and competitors to compare, if you are buried in the results they may not put in the effort to find you again. You can get a good ROI from either low paying or high paying keywords and ROI is what it's about.
I agree completely with Vangogh. What you need to focus on is conversions and your ROI.
If you haven't implemented conversion tracking yet in adwords then you should. Then watch your keywords to see which convert. Support the good ones, tweak or dump the poor ones.
I always find that creating several different ad's, all with around 15 specific keywords and ensuring that your ad contains one word from all keywords is the best way.
By just blindly clicking add to hundreds of keywords is a sure fire way to throw your money down the drain!
