User Centred Design --- without the users?

I'm a member of the Usability Professionals Association as well as a member of the World Wide Institute of Software Architects. Both communities discuss the need for user centred design. Looking at our favourite development process (make your pick: XP, Agile, RUP or whatever acronym you fancy) the users' requests always come first. While I think this is an important concept I sometimes feel uneasy about it. In most of my software projects we end up with features and design the users haven't asked for but highly appreciate. Actually I consider implementing exact user requirements as a failure.
Kathy "Headfirst" Sierry sums it up nicely in her latest post:
The goal is to add sliders that turn out to be really important to users. And I say "turn out to be", because the most daring breakthrough products and ideas are rarely driven by user requests.
Go read it.  

Update:Thx to Ganapathi to point out the typo, fixed now.