Macbook Air V-Link Peachtree Nova

Can you guys tell me what the highest quality audio file I can play with this setup would be? What program/s should I use on the Macbook should I use for playback? Any additional tips or opinions would be great! Thanks
FLAC, AIFF, WAV, and ALAC are all lossless formats, you should stick with these. Differences between them are entirely system dependent, if they exist at all. I have read that Amarra and Pure Music are both good software add-ons for Macs.
You have a DAC that can play hi res files, try some out at HD Tracks or Linn Records websites. I have not gone this route yet, and I don't use a Mac, so I am not sure about compatibility issues using iTunes/Amarra/Pure Music on a Mac to play hi res files. Depending on which Vlink you have, you might be limited to 24/96 on hi res.