Another choice is to use (say, 50%) of the value shown on the Stamp World site then donate the collection to a 501 (c) 3 entity and take a tax write off. Using 50% will show conservatism in your evaluation should the IRS audit.
Don...
Can you explain further what you mean here? Do the tax folks in the States accept donations of stamps and, if so, what do they do with them? What's the point of the process? I read something about this over on another forum not so long ago. How do they value stamps if the typical catalogue prices are miles over regular retail?