When I first wrote my homepage, I modeled my site on Debian's site which at the time used HTML tables for layout. I had never used CSS and I also felt that plain HTML would give maximum exposure.
A while later, I had to learn CSS when I wrote pages using MathML. The XHTML/CSS approach seemed cleaner and easier, and sometimes when I added new sections to my site I'd use XHTML and CSS. But I never converted the rest of my site out of laziness, and also I was worried that my site would look wrong in IE with its numerous CSS bugs.
I now feel the time is right to use CSS on my whole site [10 reasons why tables should not be used for layout]. I've spent a while trying to learn CSS properly. Additionally I've been reading about webpage design. Apparently, sans-serif fonts are preferred to serif fonts when on screen. The best widely available on-screen sans-serif font is Verdana while for serif fonts it's Georgia[1, 2].
Note I'm still sticking to HTML for now, as XHTML is not handled properly by IE or Google yet.
Now my default CSS file gives my site a kind of bluish Slashdot.org look. My only regret is that w3m will no longer be able to render my page layout (perhaps that's the only advantage of using tables for layout?), but then again, how often do I use text mode browsers?
My site is also long overdue for a general cleanup. So far I've been working on the presentation of my page but the content will also be reorganized.