If we are talking about resolution that does not exceed 16/48...
Definitely AIFF, for reasons already stated.
Having compared the audio quality of AIFF to WAV to FLAC at different times, across different platforms, using different applications, it got boring. There is no inherent difference, based on the file type. What there is, is a difference in how well a given hardware/software configuration does playback.
If we are talking about Hi-Rez (24-bit at any sampling rate)...
My experience has been AIFF consistently performs like cr@p. Tried to get to the bottom of it, but, the time was better spent on other things. In this case, for uncompressed, WAV is indeed the way to go. Having compared Hi-Rez WAV to FLAC, It has been the same experience as the AIFF / WAV / FLAC comparison.
For the record, currently using Macs w/ OS X 10.8.5, and Decibel software for playback.