Like Amazon.com, iTunes follows your spending habits and attempts to make recommendations based on your historical selections. I recently received an e-mail suggesting that, since I had bought the Guillemots' "Looking through the Windowpane" I might also like the (Band of) Bees' "Octopus". I tried a few tracks and agreed with the suggestion.
I also received a recommendation to try out a few tracks of Brian Ferry's "Dylanesque", having bought "Frantic" last year. Another selection that went into the shopping cart.
This approach seems so much better than idly wandering about a record store, turning over CD cases.