Few apps are as good as TuneIn Radio, which features 50,000 free internet stations all from your Windows Phone. And while the app has an impressive 4 1/2 star rating (from over 800 reviews), it still could be better. How so? How about getting Mangoized in v2.0, allowing it to stream and play in the background. And while that is awesome, it's even cooler to be able to pin each station to your Start screen for quick 1-touch play. Awww yeah.
Take our money, TuneIn Radio! Oh what's that? You're free? Well then, even better... Get the app here in the Marketplace. And if you're logged in to the Web Marketplace, try this link and see if that sends it to your phone. (Thanks, NickP for the tip!)