I'm a real fan of SomaFM: "Over 20 unique channels of listener-supported, commercial-free, underground/alternative radio broadcasting from San Francisco. All music hand-picked by SomaFM's award-winning DJs and music directors." All my Amazon purchases go in support of. Check it out! I listen to the Secret Agent channel the most.
For a very lightweight, Internet radio player that will run unobtrusively and minimized in the systray (you'd be surprised how hard it is to find that feature alone), I recommend Screamer Radio.
"All generous minds have a horror of what are commonly called 'Facts'. They are the brute beasts of the intellectual domain." -- Thomas Hobbes
Disclaimer: I am not a broker, dealer, investment advisor, physician, theologian or prophet. I should not be considered as legally permitted to render such advice!