Hoping to get some insights here:
First some background. For several days I have been doing some study on XHTML versus HTML. I have been writing all of my mark-up with fully-valid XHTML lately, either Transitional or Strict. It's pretty easy to do and not very far removed from HTML 4.01. I am, however, learning several things which may indicate that this is not a good move, even though W3C promotes XHTML 1.0 as the preferred minimum standard to employ currently.
Why it's supposedly not a good idea. It is my understanding that very few sites employing XHTML (including the vast majority of those "really good" XHTML-Guru sites you know of and love so much) are doing it properly. The developers are sending their pages to the browser as text/html. As such the browser is reading the page as HTML, not as an XML application as it's supposed to. Therefore the browser must go through the trouble of negating all of the extra mark-up (i.e. closing slashes />). If, however, you do send the document to the browser as a true XML application instead of text/html, then the browser doesn't like it. It'll make Moz-FF go into quirks mode instead of standards compliance mode. With MSIE it is my understanding it won't even work as XML is yet to be supported and thus won't even present you with the page render. For MSIE you're supposed to create a mirrored HTML page to satisfy that browser.
Three levels of failure. It is my understanding that a number far fewer than 1% of XHTML sites are failing in one of these three categories.
1) The page isn't valid. This is weak. If it's not going to be valid and maintain it as such, it is considered an bad thing, much worse can using very old HTML.
2) The developer makes one or two pages comply, but through laziness fails to make the rest of the site comply. This is said to be a bad thing to do as well.
3) The XML MIME-type isn't added to the .htaccess file thus making the whole thing a wash. If the MIME type isn't setup to be supported by the server, it will never be available to a capable browser regardless of how it's dished out.
My take on this. To be frank I'm confused as to what to do. Lots of mixed signals. I think I want to (and have been) making fully-valid XHTML sites, strict by preference, but I'm torn as it seems the best site to make is one written to the HTML 4.01 Strict standard. At this point I don't know what to do. Jump on the XHTML bandwagon and don't look back and do what W3C wants me to do, or to do what's probably best at this time by sticking to HTML. I'm gaining all sorts of benefits using page divisions instead of rigid, must-be-rendered structures like tables, and I'm totally sold on CSS. And PHP makes me happy. But the XHTML thing is less clear to me and I really want to make the best sites humanly possible.
Any feedback is appreciated.