I-tunes download sample rate?

I need some experience on download sample rate for downloading my Cd's on I tunes! I am planing on running ONLY! my MAC BOOK PRO to my cary new CD 303TSACD player, and my high end audio 2 channel system. Via optical cable. Not an IPod or IPhone. Also do not want to try an other downloading software for my music. Do Not Give me heck about using I-tunes! I know most audiophiles give people Fuss that it sound quality is junk. Its only because I bought a New Apple Mac Book and only uses I-tunes.

My down load options for CD's only, downloads are, WAV Encoder, AAC Encoder and AIFF Encoder.
Tell me your expericces and which setting would suit a Class a Tube system?
Come on and help a guy out"