Another niggle and this isn’t a Mac specific one, but I did wonder how to preview a song before deciding to buy it on iTunes:
To listen to a preview of a song in the iTunes Store, double-click the song. If your network connection is slower than 128 Kbps, the preview may sound jittery. Choose iTunes > Preferences (Windows — Edit > Preferences), and in the Store pane select the “Load complete preview before playing” checkbox.
Apple like their simple(ish) interfaces but a preview button next to the buy button wouldn’t have killed them! This was a little too obvious for me.