OK, several ideas:
How about just getting a CD player that will play MP3 cd's and would hook into any other stereo equipment you might have.
Another option are to get one of the new media pc's that have been designed to work as both a stand alone entertainment system and a computer.
Also, there are a couple of manufacturers that make receivers that will network with a computer and play both MP3s and interent radio stations that way.
Finally, there used to be designs by severall people who had built car based MP3 players that could be modified to work in the home.
Obviously the first option is the cheapest since any (almost) stand-alone cd/dvd player should work for that. The dedicated receiver is around $900-$1000 on the lowest models that I have seen. The other two options increase in cost from there (actually the self designed system would be cheaper money wise but would require a large time investment)
Here is a link to Onkyo's website that carries some of the receivers I was discussing.