The best place to start is google's own page on webmaster guidelines.
In short, it says to design your page for "real peaople", and not just for a SE. Provide rich content, meaning text, that is relevant to the topic/subject of the page.
However, there is a line. Google will know if you're over doing it, and specifically trying to fluff it up.
Google also "appreciates" semantically correct, standards compliant code as well. Proper tags, attributes, tags used correctly, etc.
The less "bloat" in the page, and the more content, the better. Remember all SE's, not just google, can't read any image contained in an image or a flash file. You could put the cure for cancer in a flash movie, and google will never know it's there. Also, blind persons or people with vision problems are the same way.
Extra "bloat" would be unnecssary tables, nested tables, useless tags (like font tags and junk), etc.
If you've ever selected "view source" in your browser, and read the raw html for a page, that's exactly what a SE would see, as well as a screen reader.