I am very, very, very happy with my Apple TV (all iTunes songs using AppleLossless files) and an extrenal DAC. It's easily the best interface. If you have an iPod and therefore an iTunes account there is almost nothing to setting it up either. Since you have Linn equipment, I am guessing you have a UniDisc and therefore no external DAC. I would suggest the Apple TV ($250) or a MacMini($500) and an external DAC of your choice. The MacMini gets you a USB output, where the AppleTV has only TosLink, so that may work better for you. With the Linn's (speakers?) either the new PS Audio or Bel Canto DAC's would sound fantastic.
Good luck.