Yeah, you could just ask a friend to suggest some tunes for you -- or you could download Pocket Hipster, the iPhone app that leers at your iTunes library, and then suggests replacements (the noun, not the band).
Putting aside for a moment the name of the app (I feel like "Pocket Music Snob" would be a lot less polarizing), Pocket Hipster [iTunes link] is a fun little diversion from a cadre of well-respected music tech companies: wearehunted.com and The Echo Nest.
Basically, one fires up the app, in which one meets two ridiculously monikered characters who blather on about vegan cupcakes and eBay. When you click on a little musical note icon in the lower-right-hand corner, a song from your iTunes plays, and the character berates you for your taste. She or he then suggests a playable track list of jams (previews only), which you can then buy on iTunes.