One of the best panels so far was this morning's "Between the (style) sheets" featuring Jeffrey Zeldman, Tantek Çelik and Eric Meyer. All three did a great job of showing off the power, and yes the relative ease of using valid, semantic markup and CSS for web design (the hot topic nowadays, n'est-ce pas). Though the audience was filled with mostly designers who admitted, by a show of hands, of having some knowledge of CSS based layouts, it was clear from the questions that most still feared it to some extent, or at least are weary of it. However, the job these guys did, I think, went a long ways to soothe some of the fears, simply by *showing* everybody "look what you can do and how easily!"
On an obliquely related note: I spoke briefly with David Weinberger who mentioned he was having some CSS/accessibility issues with one of his sites and I offered to give him a hand, which he happily accepted.