Segmentation questions

Hi

I am devloping a site where members can fill out info about them selves so that I in turn can better segment/target the ads more suited for them. Question is, which question should i ask besides the obvious age,sex, town and interests?

What are their hobbies, what do they do for a living, where do they like to vacation, etc.

You will need to provide lists of items for them to select, however. In general, folks won't simply start typing an essay for you to read - they'll just go somewhere that asks less questions.