Should you use XHTML or HTML?
That really depends on who you ask and what you need. You have said that *only* experts condone using HTML over XHTML, of course implying that *everybody* on the development team at .com are not experts. Oh really?
One thing you have to ask yourself is what kind of content am I delivering and who am I delivering it to? If you have users who browser your site with non-Computer devices such as phones, PDA's, and other hand-helds, then you’d need to use XHTML.
XHTML has the added benefit of using the very powerful XML language, offering countless possibilities with content delivery and delivery methods. XHTML is often a preferred method, there is no technical reason to use HTML over XHTML, but some would debate that there is no technical reason to use XHTML over HTML. -- It goes back to what kind of content you are trying to deliver, who you are trying to deliver to, and how.
If you feel that HTML is a better method for you after weighing the options, then go with HTML, but don’t try to push it on others who choose to use XHTML for their own reasons, and good reasons we do have for using XHTML.
A common myth is that XHTML is not compliant or compatible with IE7 or 8. This is simply untrue. It renders XHTML correctly (and therefore compatible), but IE has problems with the XHTML namespace and is not supported by IE. This just simply means that IE will see the document as generic XML, it will still display fine, but there are specific rules to follow, such as using display:block for block-level elements. Although this is not really out of the ordinary for designers, Web 2.0 Designers are quite used to building sites that use explicit statements and hacking IE6, IE7, and eventually IE8 to be as compliant as other browsers.
What should you do?
XHTML 1.1 isn’t logical to use because Microsoft decided not to support the future of XHTML (a very poor decision, in many people’s opinion), but XHTML 1.0 Transitional or Strict work just fine on IE, and it’s usage is encouraged. Use what is best for you, we will use what is best for us, we decided a long time ago to use the newer XHTML 1.0 Strict standard for prosilver, and I believe the decision was well grounded and has a very promising future.
There will be future developments with XHTML and HTML, and XHTML promises to easily be compatible with the future of the web, whereas HTML has it’s limitations in the area of future compatibility.