The simplicity is great. I have a single NAS containing my entire collection connected to some speakers. In another room I have a rasp pi connected to a different set of speakers which streams the music being played via Icecast2. I can control the music in either room using pretty much any device connected to the network (PC, laptop, pi, tablet, phone), and also stream my collection when not at home.
I don't know of any particular client that's similar to winamp or itunes, but there's a lot to chose from[2], although many of those are a bit dated.
[1]:http://www.musicpd.org/ [2]:http://mpd.wikia.com/wiki/Clients
