On Sun, 14 Jun 2009 21:56:07 -0700 (PDT), MKW
wrote:

Liquidity should not be a primary issue...collect for enjoyment and
appreciation of the piece...not investment. Someone who pays $100,000
to add some obscure half dollar to a series isn't doing so for
investment...its because they want that complete set more than
anything.

Sure wish I had your money...

Unless you are wealthy above and beyond your 'collections', liquidity
is ALWAYS a concern for a thoughtful collector of expensive items.