As I'm going through the "buying a home" process, I just found out that over the last three years, my credit score has gone from a 720 to a 768. I've got $40,000 in student loans that I diligently pay ($315 a month), and a credit card that's paid off every month. I was all excited with my 768, until our mortgage broker said that my wife has a credit score of 795... whoa.
I've also heard that if you don't pay off your credit card in full every month, but make consistent payments, it will help to increase your score.