Should a Buddhist "have faith"?
In the Kalama Sutta, the Buddha is reported as saying that Buddhist principles should not be accepted without evidence, and that 'it is proper ... to doubt'. Confidence/trust (sraddha) in the teachings is important, but 'blind' faith is actively discouraged. Here's what he is reported as saying:


  "It is proper for you, Kalamas, to doubt, to be uncertain; uncertainty has arisen in you about what is doubtful. Come, Kalamas. Do not go upon what has been acquired by repeated hearing; nor upon tradition; nor upon rumor; nor upon what is in a scripture; nor upon surmise; nor upon an axiom; nor upon specious reasoning; nor upon a bias towards a notion that has been pondered over; nor upon another's seeming ability; nor upon the consideration, 'The monk is our teacher.' Kalamas, when you yourselves know: 'These things are bad; these things are blamable; these things are censured by the wise; undertaken and observed, these things lead to harm and ill,' abandon them...
  Kalamas, when you yourselves know: "These things are good; these things are not blamable; these things are praised by the wise; undertaken and observed, these things lead to benefit and happiness," enter on and abide in them.


Kalama Sutta: The Buddha's Charter of Free Inquiry