Since my current desktop is Redhat 6.2 running Gnome, I use XMMS. And yes, I too have fallen prey to eye candy and pretty gui's
I wish Sonique were ported to unix though.
Here are some of the sites I listen to:
Radio Cubik Network
Tag's Trance Trip
Tag's Trance Trip and others
R.I.P: Tag's Trance Trip