Neil Killick suggests in his blog that it might be time to think about getting rid of product backlogs. Intuitively we think that it's a good idea to keep a running backlog but Killick has another way of looking at things:
I actually now believe that constantly adding, removing and tailoring requirements (or stories, use cases, whatever) on the Product Backlog is (especially in the wrong hands) a fairly ineffective and costly approach to building software.
-- Neil Killick, Should we get rid of the Product Backlog?
Take a look at the post to read his bulleted list of seven reasons why you might want to ditch the product backlog.