The favorable rule allowing debt forgiveness on a principal residence mortgage up to $2 million expired at the end of 2013. It could be extended, but given the resurgence in the housing market, it may not be included in a package of extenders this year. Stay tuned!
Generally, an unmarried person who maintains a household for dependents and is allowed to compute his or her tax based on head of household rates, which are more favorable than single person rates.