Definately color hardcover for me, probably at my FLGS, though I'd look into getting PDFs, too, especially with some discount (hint,hint) with the purchase of the dead-tree versions.
As stated elsewhere, a hardcover (especially w/ kickass art) will get looks at a retail store. At my FLGS I look at the covers for [the other game]'s products, even though I will never buy one. Sort of self-advertising. If the store won't order extra copies for display, guess I'll have to order an extra set for them!