As long as there will be SEO we will have debates. Questions like how does Google index a site, how does the Google bot read my site, what should come first, what should come next, do the file extensions matter (no, unless they are .exe), do slashes in the URL matter, are deep pages less important and so on, and so on.
Google is so much different from the other search engines. Its algorithms are better, more sophisticated and provide for proper indexation for all scannable files, if they are relevant. So instead of worrying about such details, you should really worry about providing quality for the users.
The “quality” principle extends over coding and the actual product you deliver to your visitors. Improper coding lowers your chances to get that “Google love” you long for. Any technical difficulties on your website might lead to accessibility issues and these will give you lower rankings in Google’s new ranking algorithms.
Really, we do not need to engage in endless debates about the importance of valid codes and accessibility. Just do your job right. If you come with the argument that Google doesn’t validate, I just have to counterattack and say: it will.
So don’t hide behind such a lame excuse. Hire a decent company to fix your technical problems now. There are a few quite affordable, including SEO Ltd. Don’t fall for “submit your site to 100000 search engines” clichés. SEO is not about that anymore. And avoid questionable SEO tactics at all costs.