>If you don't typically purchase at Starbucks, then I'd try either a Java Chip (or Mint Mocha Chip) Frappuccino and/or a white chocolate mocha. Get it affogato so that the mocha or caramel is on top of the foam with a shot of espresso syrup poured over that. Make both something different so you can get a taste of their specialty drinks. Whatever you get, make it a Venti (20 oz) size. :o)
And the Italians are famous for their metric ounces :).