The D40, by all accounts, is an outstanding camera. An excellent starter camera; a wonderful Point & Shoot, for someone who wants to lug a camera around all day and what makes it so sweet is its price. You can easily master it, and get outstanding results with it.
That said, look at the options out there. As has been said, a new D40 is only £30 more, but £30 will buy you a couple of memory cards and a spare battery.
Just shop around and you can't go wrong, one way or the other.