If I were you I'd export Pro Res. If you want to work with the material in the future, it will stand up well under several generations of re-encoding. It's very close to lossless and is a fraction (maybe a quarter?) of the size of uncompressed.
As far as export time is concerned, it should be fairly quick. I've found that FCP X exports even unrendered Pro Res sequences very fast…II almost never render anything unless it's an effect that won't play in real time.
Best of luck.
Thank you so much for your exporting advice Russ, and also about almost never rendering.
When you speak of ProRes here, are you suggesting ProRes 422, 422 (HQ), or even 4444? Would 422 be sufficent for my needs do you think?
Also, should I always transcode my original clips to 'optimized media' in FCP X; does this speed up the editing and export?
Optimized media in FCP X parlance is Pro Res 422. Here is a very good article on Proxy versus Optimized.
If you were adding a lot of graphics to you movie, or if you were sending it to a professional for color grading, there might be a case made for PR HQ. But for most people, PR 422 is perfectly fine. BTW, Pro Res 444 is PR HQ with an alpha channel added (for transparency).
Apple just out with somethirrg on native editing; notice that h.264 was not among those that will edit well. It will edit but it's easier in Pro Res…and it's my opinion that Pro Res treats graphics and text better. Whether it exports faster, I'm not sure. As I said I find exporting Pro Res to be rather painless,