Pardales, any Apple computer and an external hard drive can do what you're looking for. The G5 models have built-in digital (optical) I/O, but require an external monitor. The laptops and iMacs would require an external digital connector such as those offered by M-Audio or Apogee. All the Apples include iTunes software as part of the purchase package. Such a system will also perfectly integrate with an iPod to add portability to the listening. Apple.
Yes, I own stock in Apple.
Yes, I own stock in Apple.