So I was at a P2P conference last week, and learned that Schering-Plough was going to be one of the speakers (they started using Ariba nearly 7 years ago and continue using it today).  What I hadn't realized is what a great job they'd done with establishing their baselines, and metrics so that they could report on the savings they got each year.  What they said at the conference was that last year alone, the Ariba solutions saved them over $200M!  Now if I could only find a stock market with that kind of return!