I think that more and more designers/developers are starting to realize that the table element isn't the future for web-layouts (actually tables are never meant for layout at all). But that's not enough. More and more people are trying to use XHTML or HTML in a better way, but they don't know everything. That's one reason why some people are weblogging, to teach!
To make the step from a "table-based-layout" towards a "standard-compliant-layout" they need to be convinced. There should be examples (like CSS Zen Garden), these should be listed and available for everyone. And that should not be those weblog layouts like mine for example; those are ugly in the designer's eyes. For us it's important that it's readable and understandable. But a designer wants to see a good-looking design and nothing less.
Some designers are thinking that Netscape Navigator 4.x is important! No it isn't! A very few people are using NN 4.x. More people have disabilities than people are browsing with NN 4.x.
But that's from the designer's point of view, they need to understand. Now back to us, the developers/designers who are teaching/learning web standards. We need to improve our own sites first before we ever go to tell a designer what to do! Why aren't you using the ins and del element for marking up changes in you weblog? These elements are well explained by the W3C and still nobody knows them.. Of course I don't expect anyone to read the specification, but if the element was used by people who read the specification then the web would be a better place.
Also some people (including me for a while) thought there was no real use for the br element. I agree l (part of XHTML2.0) is better markup, but that one doesn't exist right now. How else do you want to force a line break within the address element (did you know that one?). Eric's Meyer favorite example is: "How else do you want to force a line break within a poem. And "we" are damn right. Its useful for now. Same as using the hr element to separate items, it's not for layout!
And if you use the right semantic markup, check every time when you updated a part of you site: "Do I still validate?". And the XHTML is more important in this one, since a browser is programmed to ignore invalid CSS, Mozilla on the other hand crashes when my XHTML is not well-formed (which does not guarantee I validate). So I suggest that you convert you websites. Make them standard compliant and that you are going to use the correct MIME-type for you sites. If every developer/designer who is aware of web standards is going to do this we may convince other people who are interested and who want to learn.
But if we are first going to wait for another five years, while we tell each other how perfectly our XHTML Transitional validates, then the web is doomed to be not-standard-compliant, inaccessible, not usable forever. And that is an understatement ;).