I found a great program called WebMake which totally solved my desire to simultaneously have a website written in Ã¼bersexy XHTML and one that Google and IE can read.
WebMake is one of many website generators out there, but it just clicked with me. It allows me to have all my content in one file, and from that file, generate both HTML and XHTML versions. I hear that I could also massage it to get easy translations of my pages.
Providing both HTML and XHTML versions of webpages is, in my humble opinion, the best solution to the whole "XHTML is the way of the future, but IE is living in 1996" problem. You can offer fully-compliant, properly MIME'd XHTML to those browsers that negotiate with the Apache server for it and everyone else gets last year's HTML. And better yet, this is all done with no hacky .htaccess tomfoolery. Yay WebMake!
I did run into a couple problems though; the documentation is decent, but doesn't cover all the crazy cases I wanted. I had to fight with it for a while before I realized how to get conditional markup and had to work around a silly bug in its XML parser when using parametized content. (Perhaps I should share my WebMake file for the benefit of others.) But, on the whole, it was an accessible program that made me very, very happy.