Quote from money.msn.com   http://articles.moneycentral.msn.com/Banking/YourCreditRating/BuildAKillerCreditScoreIn2008.aspx?page=2

Don't close accounts. Fair Isaac has made it clear that closing accounts can never help a classic FICO score and may hurt it. With FICO 08, that's even truer. The new scoring formula wants to see evidence that you are actively and responsibly using credit. So you get more points for having open accounts in good standing; conversely, having a higher proportion of closed accounts can hurt you more.