The way I look at it is
is it better to have the lower intrest rate or the higher FICO score
Right now it is better for the lower intrest rate. So I looked for card that offered 0% on BT
and transfered my balances to them. It has helped my score somewhat because I have a new card and therefore more available credit.
check your fico score and then check out cards at whogavemecredit.com and financeglobe.com
as well as looking at this fourm to see what scores get approved for which cards.