I have a general design that I think is near impossible to create without using tables. Even with tables it wouldn't be a very easy to lay it out.
I mocked up the layout as a PDF. You can download CSS Challenge.pdf or go here.
The simplest example of the problem is that I have an image that I want to align left, then on the right I have a column of text. The text should by vertically-aligned to the bottom of the picture. This leaves some whitespace above the text, but there is no way to know exactly what height this whitespace is. All of that is do-able with positioning. But my problem is that I want a single line of text to be centered in the whitespace, and I don't even know how big the whitespace is.