In response to the multitude of reviews on this website promoting Hillary Hahn's recording of the Barber Violin Concerto over Joshua Bell's performance, I'd like to offer a contrasting review.
I must admit I have only listened repeatedly to the Barber on both of the aforementioned discs (having only heard the rest of the CDs maybe once). Although some reviewers have said they listened to the Bell recording until they bought Hahn's CD, I would propose you go back and listen to Joshua Bell. Whereas Hillary Hahn does a splendid job, technically perfect and quite musical, her interpretation is very cut-and-dry and not very adventurous. Simply put, Joshua Bell's performance is more personal. Not to suggest his rendition isn't technically and otherwise emaculate, but he offers something more. There are aspects of Bell's performance that are probably not written on Barber's music (you can tell because they don't exist on Hahn's recording). Things like rubato and slides are very human and don't come through clearly enough in Hillary Hahn's relatively machine-like rendition. In contrast, Bell's playing is far more like singing than hacking away at a violin. Were Barber alive today, he'd probably want to listen to Joshua Bell.
In short, if you want a comparatively bland introduction to Barber's Violin Concerto, go buy Hillary Hahn. If you're looking for something that will move you, you must buy Joshua Bell every time.