
I'm kind of in the middle on this one. I'm anti-docking in non-working dogs, and can't wait till the day I can finally rehome a whippy-tailed dobe :p
But with dew claws, I think it depends not only on whether the dog will work or not, but on the breed. Of mine, I have two with and two without dew claws - the two without are my dobes, the two with are my rott mix and labracollie. Neither of them have any problems at all with their dews, and the claws are small, neat and close-set. They use them to keep chews and things stable.
But having been a groomer, I've seen the flipside - I've seen pyrenean mountain dogs with huge, very freely movable front and rear dews that could easily catch on something; and I've seen cavvies with horrendously long dews that have been hidden by long fur.
In addition, my first dog had to have hers removed - she ripped them several times digging in soft earth. She was a springer X irish water spaniel, and hers were fairly large and motile.