Although I agree whole-heartedly with Neil's serifed recommendations, if you're going to pair it with a sans serif I think Zapfino's humanist nature really calls for something more like Myriad, Gill Sans, or Frutiger. Rotis Sans and Futura would not make my list: too rational and constructed to go with Zapfino.

You could probably pair Bickham Script with Rotis or maybe even Futura, though. It would also work nicely with Kepler, I think.

Cheers,

T