I'm nuts for their first chronograph, the Porsche Design Titan automatic. Kind of ironic how, in the late 60's, IWC felt the sales of chronographs didn't warrant the investment to develop their own movement. IWC recognized the movement built to their high standards would cost much more than other chronographs on the market, and might have a hard time finding buyers. IWC also didn't have "faith" in the movements created by Zenith (beat too quick) and the Breitling/Heuer/Buren/Hamilton/Dubois-Depraz group (who didn't want IWC modifying the movement, AND taking profits from the others in the group).
Yet the introduction of the IWC Porsche Design Titan chronograph, with its now ubiquitous Valjoux 7750, seemed to reignite interest in mechanical chronographs in 1981 when they were first sold, after years of dismal chronograph sales results through the late 70's. In fact, Valjoux and Zenith both reconstructed the machinery to begin manufacture of chronograph movements again due to the demand from other manufacturers (Ebel and Waldan International come to mind). Thank goodness they hadn't destroyed the machinery and old stock of movements as they had been instructed to do by management!
Sorry for the long intro...I just translated a large portion of "The History of IWC" by David Seyffer, curator for the IWC museum. Fascinating stuff, but a slow process to translate German to English (I do not understand German!).
Lately I have been entertaining the idea of getting a different model. My problem is, since I love chronographs, I love all that IWC has ever offered! Although, to be completely honest, I prefer the sporty designs over the elegant and dressy Portuguese models. But one day, I think a Pilot on a bracelet is the one to get (a 3777 with the altimeter-style date window). Then I think a Doppelchronograph would be interesting. Then the GST (successor to the Porsche Design line) piques my curiosity.
So what's your favorite IWC chronograph? GST? Pilot? Aquatimer? Ingenieur? And, as always, PLEASE post eye-candy!