Well, I suggest you chip away at the 141 HTML validation errors and 37 odd css errors.

http://www.w3.org/ provides a lot of information re validation.

Thanks; I'm already working my way through a Google search of validation sites and compatibility tutorials. I thought perhaps someone out there might have b2evo specific ideas, especially since much of my site is based on the photoblog template.

The b2 skin/template, photoblog, passes validation out of the box.

Well, I've modified it quite a bit. I did say "based on". This is why I need help :)