Any useless species?

A question sent to the Guardian's answer board: Are there any genuinely pointless species in the world which, if they were extinct, would have no material impact on the food chain or general homeostatis? Surely no one would miss wasps, for example. 
A quick glance through the comments provided no good answers in TPP's view, so here goes.
What a pointless anthropocentric perspective you have!  Species aren't there for humans, although many aren't here any more because of humans, and some have benefited from their interaction with us.  All species interact with some other species.  When a species goes missing, one or more interactions in the great network of being are lost and the fabric of life unravels a little bit more and becomes a tiny bit more fragile whether we would notice this difference or not.  Your question illustrates one of our great problems.  Humans see themselves as apart from nature rather than part of nature, and to place values on nature from just a human-perspective is just wrong.  And, yes, you would probably miss wasps, although probably not directly. 
Any readers want to provide an answer?