Hey BB
xhtml is just really clean html, gives your content to code ratio a boost.
Its easier to code with once you forget all the old tags you can't use anymore, less to remember!

It plays nice with .xml, .rss too, which is what .xhtml was actually created for.
CSS gives the same content to code boost, plus you can control your whole site from the single css file.
Optimized images just make things load faster.
I forgot to add the top menu on that template lol, I'll see what I can whip up here?
cheers