I listen to a lot of music during a workday. A real whole lot, and I get bored with my existing iTunes library. So would you if you listened to music 8 hours a day. I need it to concentrate, but I can't download music fast enough to satisfy the demand.
Sometimes I go in the opposite direction and purposefully play two songs on repeat. This actually works best for multi-hour concentration-fests. An unfortunate side-effect is that the songs do to my brain what boys in love do to tree trunks with pocket knives. If you peeled open the side of my head, and I beg you not to, you would see deep gougy scars left by these multi-hour song-repeat marathons. (It must be two songs, in case you're wondering. Not one. Not three. Two.)
I've tried internet radio. Not bad. Pandora at www.pandora.com is pretty good for listening to music you haven't heard based on music you already like. I also recently discovered www.criticalmetrics.com. It keeps track of recommendations and playlists from all over the place so you can try all sorts of new music. I'm currently listening to their 100 Songs We Love playlist. I'm on number... um... 32: Laura Barrett - "Robot Ponies."

There's always listening to videos of course. Don't forget ol' James Burke. Great narrator.
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