Pr has a different "mindset" than FCP. FCP converts everything to an intermediate codec (normally ProRes) And in FCP you can choose different "qualitites" of the prores codec. But you cant make better quality than the original.
Pr edits video in it's native format. So there is no need for conversion or or an intermediate codec.
So; for exporting the question to ask is; what format is needed for the destination application?
Two that spring to mind are the Lagarith Lossless and the UT CODEC's.
However, as Curt points out, the exact use might well preclude the use of those, and suggest something better/different.
Depends on the codec your coming from. AVCIntra is the best codec option native to CS5 quality to compression level for compositing. Cineform's codec is great if you have one of the Neo Products. Those are your best options for that kind of work. The main time you need to worry about it is if your acquisition codec is highly compressed like AVCHD or H264.
Thanks eveyone for your responses. When I archive a finished master spot (or do any compositing) I want the footage to be locked into a codec that preserves the intergrity of the original and reduces the file size. That is why I really like Prores. I guess I can use that (which is not native) or AVC Intra
(which is) for these uses. Since I have FCP installed on the same Mac I do have access to Prores as a playback and creation codec. It just can get to "messy" doing alot of motion graphics in XDCAM or H.264. I can deliver in those, but I want the final master to reflect the high quality of the original footage (kind of like storing a spot shot with a betacam as a finished master on a digibeta tape as opposed to a VHS ;-)
I would use AVCIntra then. The files wont be astronomically large and you will keep the quality you want. Also FCP and Avid can bring in AVCIntra into one of their Intermediate codecs.