"Because the company I work for makes a percentage of the total spend, we could, conceivably bid these companies against each other for the same terms, thus increasing the spend for both companies, and thus making more money from both."

I think this one will be a hot thread, many of the issues raised will related to PPC's older and wiser brother SEO. I'm expecting a great post from Andrew Goodman even though I'm sure I won't agree with a single word of it.