Avi,
I recently had a similar question in this thread.
Short version:
For software players MediaMonkey, Winamp and Firefly were suggested. I have used Winamp with great success so far.

Hardware devices - Squeezebox as already mentioned, but you might also want to check out Sonos.

Cheers.

Dan
On-Wall M5HP LCR, QS8 & EP500 in 7.1