This post from Shut Up and Sit Down spend sometime talking about the best intro games to tease your Euro playing friends to the dark side of real gaming. Most are block games.
Which is ok.
My recent forays with Hannibal Rome v Carthage give it an old school nod. Combat Commander in Europe is a great game for someone who is interested in the Tactical level.
AS a fanboy I would be remiss to not mention the World at War, Nations at War series from Mark Walker. EASY, fun, tense and narrative rich games.
What are your ideas?