Cascading Style Jesus H. Christ

[jough]

XHTML is "eXtensible HTML" - not Xtreme.

You can read the W3C's (they're the people who provide the language specifications to browser makers) FAQ about HTML and XHTML here:

http://w3.org/MarkUp/2004/xhtml-faq

You can also read up about the differences between HTML and XHTML here:

http://www.wdvl.com/Authoring/Languages/XML/XHTML/dif.html

If you already have HTML pages, there's really no point in converting them unless you want to take advantage of the new features of XHTML, but if you're coding from scratch, I'd HIGHLY recommend doing your new pages in XHTML 1.0 Transitional so that you don't have to completely re-code everything when you decide that you DO want to add more complexity to your web project.

My $.02.