Wow. American Express must be getting desperate. In a bid to RID itself of customers, Amex will give you a $300 prepaid credit card if you cancel your account. According to CreditMattersBlog, it is offering the deal under the guise of enabling customers to "simplify" their finances.
For more news on American Express, check out this page on Consumerist.
And here is some more information on Amex.