If you convert an AIFF or WAV file to FLAC and then re-convert it back to an AIFF or WAV file, you'll end up with EXACTLY the same music. There are no "compression artifacts". It's the same as if you zip a text file then un-compress it. You don't get artifacts in your text. That is why it is called lossless compression. If it affected the un-compressed music in any way, it wouldn't be lossless.
I think I worded my post rather poorly. My reference to compression artifacts was referring to artifacts that may have been introduced by the conversion software, not artifacts inherently present in the .flac codec. I have tried several different conversion software programs and ripping programs and not all of them perform their functions with the same degree of precision and accuracy.
I still believe that the least amount of processing and/or conversion between codecs will result in the best overall sound.