Worth pointing out that Child Benefit is not a needs-based benefit. It's available to all native Britons & those with ILR who have 1 or more children - the amount varies depending on the number of children, the age of the children & whether older children (ages 16-20) remain in full time education or not.
I think Weby's suggestion about banking it for future education (if you don't need it now) is a good one.
It's probably going to be cut or reduced along with everything else - apparently, higher-rate taxpayers will not receive this benefit from 2013. There may be other changes too.
cross-posted historyenne
I don't really see why a person wouldn't claim it. If you were doing your taxes in the US, would you not claim the exemptions to which you are entitled (for being married, children, household, etc) - because you didn't need that tax money? If not, then fair enough.