Apple Lossless, AIFF or WAV for itunes?

I have ripped my collection in itunes to AIFF but as I consider buying a NAS I here most are not compatible with AIFF this true? Of the three which is best for sound quality and maintaining the correct metadata?
Thanks for your help!
FLAC or ALAC. Both lossless. One is controlled by the Evil Empire, your choice...

Flac its a good option, open source.
As long as you have up-to-date codecs and your processor isn't so low-powered as to struggle with decoding flac or alac, then all 3 will sound identical as all are lossless. Also the 'as long as" scenarios described in this post are not common. Just go with flac or alac, whichever your system supports, or flip a coin for either if both work without any tweaking.
I have noticed in my system that wav sounds better... even using dbpoweramp to convert flac to wav, the converted files sound better... Can't coment on AIFF as I use PC, but thought it was worth mentioning.
.wav has the best SQ, but AIFF maintains the tags and SQ hit is not too bad. Any format can be saved on the NAS.

Steve N.
Empirical Audio
Since you said "for iTunes" you won't use FLAC unless you use
a third party player software that works in tandem with iTunes since iTunes
does not directly support FLAC. my choice would be AIFF or ALAC
because of the metadata support and I personally do not hear a difference
between any of them.
I use AIFF. Haven't spend much time comparing the different formats because I find this sort of A/B testing tedious. AIFF seems to be a nice compromise between tagging ability and lack of compression. General consensus seems to be that WAV has the potential for best fidelity while FLAC/ALAC may not sound as good. Storage is so bloody cheap why bother with compression at all? I mean, this is a site dedicated to maximum fidelity, correct? What's a few hundred bucks extra for storage capacity in the context of a most of our systems?
WAV. I have a WAV album downloaded from Juno that sounds much better than a FLAC rip through my Naim DAC. In fact, I'm astounded how much better it sounds. Only if WAV was more readily available to buy.

If you are comparing a download (WAV) with a CD rip (FLAC) you may well be comparing much more than the difference in audio codecs. They might be entirely different masterings or mixes. Unless you could be certain they are from identical sources you could not be sure.

You could rip your CD to WAV and then to FLAC and that would ascertain a valid comparison.

I have compared flac vs wav rip of the same CD on my Naim dac and wav has more immediacy to it.

I was curious to how a purchased wav album sounds so different than my CD wav rip. Like you said, could it be a different mastering or conversion process to wav?