Last week, Jonathan Simon posted on Google Groups about the questions and answers he received while at Las Vegas Pubcon 2007. For reference, here are some of the questions and answers that were discussed.
PPC vs. SEO
Google recommends that if you're already getting a lot of visibility with PPC, you should still make your site search-engine friendly. As Jonathan says, "don't just roll the dice, make it a sure bet."
SEO focus for Large Sites
If you have a huge site, focus on SEOing the entire site, not just some core pages.
To be informed of mentions of your company, subscribe to Google Alerts or to an RSS feed of Google's blogsearch for your particular search phrase.
Additional questions and answers are provided. The full read and discussion is at Google Groups.