Lou always inspired me. I taught a case on his leadership style even before he joined IBM nearly 25 years ago 🙂
He’s the man who turned around IBM at the worst time of its history at the end of the 90’s.. Before that he also revamped American Express and other companies after having started his career with McKinsey. Lou is now 74 and still comment on corporate leadership   http://www.mckinsey.com/global-themes/leadership/lou-gerstner-on-corporate-reinvention-and-values
I always point out Lou Gerstner when I’m teaching the evolution from sales-oriented  to customer-oriented companies. He showed the way to change in corporate culture as a core ingredient of strategy.
Read his book Who Says Elephants Can’t Dance? (HarperBusiness), it’s now a classic ! 
http://www.forbes.com/2002/11/11/cx_ld_1112gerstner.html
Jean-Pierre Baeyens 