Mainstreet.com has a useful article giving a few tips on topics to avoid bringing up during your interview.
Number one on their list is railing about previous employers; even if you leave an employer on less than amicable terms, turning the other cheek and focusing on the positives is the way to go. Criticizing can give the interviewer the impression that you'll be feeling the same way about them a year down the line.
Other topics the article suggests you avoid bringing up include childcare, financial woes, and your age.
Read the full article at http://www.mainstreet.com/slideshow/career/employment/5-touchy-topics-avoid-job-interview