I've been using Grooveshark pretty much all the time now. It's not as polished as the other apps, but it's got a great selection and it's been super solid for me.
I like tunein if I am trying to find a specific station, if you pay for it then you also get the ability to record and playback streams. I like Pandora for general streaming, lastfm is good too. I prefer spotify for specific artist streaming, and Google play for streaming my own collection.