I support the recommendation to use Apple Lossless due to the superior tag support. On that topic you can use Apple Lossless in Windows Media Player complete with tag support including embedded artwork if you have the right plugins installed.
I would suggest having your master computer rip to Apple Lossless and store directly on the NAS, and have the NAS set to run Firefly to 'share' the music across the network. Another computer - your Nettop can then use iTunes and connect to Firefly and play the tracks.
AIFF, WAV, Apple Lossless, and FLAC are all lossless and contain all the original audio information and should sound the same. You can convert from one of these formats to the other with out loss hence the fact they are all lossless formats. I am recommending Apple Lossless because unlike FLAC it works in iTunes and on Apple devices. Apple Lossless is now an open free format just like FLAC. Arguably Apple Lossless has wider software support, it can be played (amongst others) in iTunes, WinAmp, dbPowerAmp, Foobar2000, Windows Media Player, Microsoft Media Center, VLC, Mplayer, XBMC, Plex, etc.
I have my entire library in Apple Lossless (ripped by iTunes) and stored on a ReadyNAS and shared with Windows Media Player, Microsoft Media Center, Logitech Squeezebox, and others.