I'm building a small social networking website for a university project and this question is purely a cosmetic thing.
Basically, my tutors are really anti-table and are very strict on the fact you may only use them for tabular data, but I am not really sure what is and what isn't considered tabular data. Would an inbox be considered tabular data? I would quite like to use zebra striping in displaying this and as the data is rendered dynamically in a loop it would be a pain to do this with CSS and divs.
When, if ever, would you use tables?
I would agree you want to use tables when display tabular data so yes an inbox would be an ok time to use tables. The big concern I think people have with tables is when you use them for layout of the entire site. Use div's to layout the site and then tables to display tabular data.