I love each of them equally for different reasons.
His first release When This is Over I love because I feel it is his strongest lyrically.. It's very raw because he made it with money he'd won from a radio contest
His second release The Old Prince, I feel is the best lyrically/musically accessible.
And his third release I feel is his most accessible/radio worthy. Probably his best to get into initially and then back track. I honestly can't pick a favorite. I feel most of my favorite songs of his are on the first album though. He's just consistently awesome, so it's difficult to pick.