OK, OK, I’m a bit slow with this one…
In iTunes (unless you’ve turned them off in Preferences) there are little arrows beside the entries in the columns which take you to relevant pages in the iTunes Music Store.
Did you know that by holding down the option/alt key you could use them to jump to relevant places in your own iTunes library? Much more useful. And you can toggle this behaviour so that using your local library is the default and you need to hold down Option to go to the Music Store. Very nice.