I know Maxine is always looking for suggestions for presentations on CSS. So here are couple of topics I would of liked to seen last year. So they are no longer bleeding edge and now targeted at the other 90%.
1. Advanced CSS layouts, Kevin Yank has already covered this with "Everything you know about CSS is wrong" suggestion.
2. CSS frameworks, what they are, why you should use them, which are the better ones.
3. Progressive enhancement with CSS2/3. Features you can use now, to enhance your design for modern browsers, without breaking old browsers. RGBa, @font-face, border-radius, border-image, text-shadow etc.
2 or 3 could either be full 50 minutes presentations, 50 minute panels, 25 minute quick fire presentations (with lots of links to resources) or all could be combined into a full day workshop "Advanced CSS Skills" with the addition of a couple of additional topics like:
Typography: Font stacks, type scales
Grids: Why you use them, how to use them (tied to CSS frameworks).
The final session should probably be bring us your CSS problems and we will find a solution.