Ian McAnerin & Anduro Technologies have put together a very clever and useful tool called the SEO Browser. The site acts as an interpreter, giving you an opporunity to view a web page as a very basic search engine spider might see it - with the graphics, formatting, CSS & layers removed. The plain text version of a site with only it's links to define it makes for a good experience and also gives great insight into the ease with which different content sections can be parsed out based on their phrasing and spacing.

The browser also offers advanced functionality for a price (right now it's listed as $7-$249), but the site does not say what these additional features might be.