Matt Cutts links to a video called, SEO site review session from Google I/O 2010.

Here are some notes from it. They're in the order they were brought up in the video, not order of importance.

1. meta name “KeyWords” is not used.
2. A good meta description is useful.
3. Put the text that users will type into your page. (Or allow commenters to provide further useful description.) Look in your server logs.
4. Keep your CMS up-to-date. Sites get hacked. Protect (chmod) wp-admin. A lot of Googlers' own sites got hacked. (Sounds familiar.)
5. Title text matters.
6. Useful words in the URL are good. Page content is even more important, though.
7. Use Google Webmaster Central (It lets you know if it has malware on it.)
8. Google Web Toolkit (AdWords written in it.) Ajax more crawlable.
9. Google Skipfish
10. http://google.com/webmasters
11. Owner Verified Listings in Google Maps
12. In URLs, use dashes to separate words rather than underscores. (Google processes words with underscores as one bigger word.)
13. Show related content on the page. Works great for YouTube.
14. Be consistent with your internal links. (Use rel=“canonical”) (Use or don't use “www.” and “index.htm”, etc. consistently.) If you use different urls for the same pages that'll divide up your page rank amongst them.

Google, Search Engine Optimization, AJAX, crawl.