Others have already said this, but, as a professional web site developer (and an aspiring perl hacker), DON'T do things like removing quotes. Many people code sloppy HTML (ok, many HTML authoring tools - particularly the WYSIWYG ones - generate incorrect HTML syntax), and some browsers are tolerant enough to get by.

But, as XML becomes more prevalent, people will need to ensure that the markup complies with the DTD. That means as well, including end tags, and not letting user agents assume where missing markup should be.

If you are concerned about the size of the page, use CSS to reduce repetitive markup. Now, what about all the other cruft your pages may have? Any animated gifs? Bloated background graphics? Are there lots of embedded tables to overly complicate the layout? These are places to save considerable file size.