Absolutely agree that it isn't the tool, it is the user. You've got to figure out how much as sale is worth and how much you are willing to pay to get a prospect in the door. Once they deliver, it's up to you to close the deal. If you can make a few thousand in profit on a customer, then why skimp on lead generation? Even if only one customer closes, it's probably worth the cost of the clicks.

I've used Overture very successfully in the past and find that their advertiser tools are much easier to use than Google's. In particular, the keyword suggestion tool showing actual monthly traffic estimates and the current bid tool showing high bids is extremely helpful in planning a campaign. If Google Adwords has something similar, I have yet to find it. (Apart from their keyword suggestion tool, which doesn't give traffic estimates).

Wondering if anyone has any good suggestions for Google campaign planning and bid setting, or do you just guess at first and adjust accordingly?

Thanks.