I'm so tired of people discounting HTML Tables. I'm a huge fan of CSS, I'm fully aware that it is possible to do columns using CSS, but in order to do so, you have to use a variety of hacks, and those hacks change based on a variety of circumstances.
With DNN, because we have skinning, we already have the needed separation between content and presentation. Tables are the best way to handle columns. They are rendered consistently across browsers, are clean, and easy to read and use, and provide capabilities that are very hard to get without Javascript hacks in CSS.
I've spent countless hours trying to work around problems with my CSS based columns due to one need or another. I've researched many approaches to the best way of handling them. None of the solutions I've seen have proven to be nearly as clean and easy as just using tables.
If you continue to feel compelled to build tableless designs, go for it, perhaps you'll have better luck than I, but when you have a complex need and you can't find a solution that works consistently in all browsers, I give you permission to just go ahead and use a Table.