Almost. There is a hirearcy. Not all text is created equallyt. For example text inside tags such as header <h1> or in <b>, <em> or <strong> tags are often given a heigher weighting than text that is very small in size. Likewise text in side anchors (links) are given special treatment. Text in alt tags is important, but not as important as normal paragraph text.Would i be right in saying that the words you place inside alt boxes of images are just as valid as actual text on the page?
Also the position of text in a page. For example text at the begining of your body html is given more importance than text at the end of the body html.
Aside form your own pages, the text on pages that you link out to, page that link in to you and the text in the actual links to an from your pages plays an important part on how your site is categorised and ranked.
Text in the head section of your html (e.g. title and meta descriptions) can help. But they have very little weighting for ranking purposes as they are prone to abuse by people puting in meta information that does not match the actual web page. The search engine generally don't like being feed a different version of you page content form what normal users see. The find such special text gets abused and spammed.
Google and others are capable of indexing and ranking pages made with flash. They don't always, but if the site had a good PR then they would make the effort. The main problem with sites that are entirely or almost entirely flash is that there is not url that the search engines can point to other than the home page. So the abillity of the SE to point the browser to the exact point on your site where the info they were looking for is stored, is reduced significantly.
The more text you can put into common or garden html, rather than locked up in flash, the better your SEO will be.