I have 2; I use my citi card regularly and I rarely use the chase (I don't even carry it around, my mom has it--and no, she doesn't use it!). And I never carry a balance--I pay it online within one week of using it.

Oh, and I have a Macys card (which can also be used as a reg. CC). I use that one a lot, but again, I pay the bill within a week so no interest fees. And I have a VS card that I've only used once.