Amarok
Let me just be the 57th person to blog that I like Amarok. A lot. Best audio player ever, and like many Linux users I've tried a lot. XMMS, BMP, MPD + lots of clients, Rhythmbox, Quod Libet, Banshee, some others I'm probably forgetting. Clearly Amarok is better than Winamp (especially modern-day Winamp). And I like Foobar2000, but I think Amarok beats that too. Automatic lyric fetching and album cover art downloading is the greatest thing ever. Among other things.
I have no problem with the addition of Magnatune. My concern is: if Magnatune disappeared tomorrow, would Amarok still exist, and would Amarok still work? I can see no reason why the answer would be anything other than "Yes", so who cares? And as per their motto, I do think Magnatune looks like the least evil music store I've seen. It's a worthy goal to promote it. I haven't found much music on there that I like, yet, but I'll keep looking.

Can it play .mpc lossless audio? XMMS/BMP can. :)
Possibly. It uses xine as its backend.
I do think Magnatune looks like the least evil music store I’ve seen. It’s a worthy goal to promote it. I haven’t found much music on there that I like, yet, but I’ll keep looking.
What kind of music are you into? Maybe I can recommend something…
-john
Metal mostly. German metal in particular. I did find some Celtic music on Magnatune that I liked.