[BScout]

Picture always uses 48k (or a multiplier -- ). There are multiple reasons for that which trace back to the development of optical audio and frame rates that dictated that. Probably above what you want to know. If you want to know, look up the history of audio on film (and then television.)

If you aren't doing CDs (and even if you are), 48k is a safe bet. Apple MFiT will accept 48k. Today's decoders in most digital systems aren't limited to CD standards of 44.1k. If you need to go to CD 44.1k, you can sample-rate convert down. You can sample rate convert up to 48k but it is obvious due to not being able to re-create what was never there (there's a band of frequencies that will remain "blank")

Officially, the original CD engineers wanted 50k-60kHz (due to filters, not the Nyqvist theory) but that was over ruled at Sony-Phillips due to the medium at that time.

So use 48k. If you are using plugins, they are oversampling above that anyway (almost all the good ones). Even better, stick to 32 bit floating point until the end.