What is the exact mother board in the first combo? if its a quality board, it might be a good deal, other wise i would say either the:
-tekram bx board with celeron 566, as long as you believe him about it still working, i could see it being alright though.
-abit bh6 with celeron 300@450, its an abit board, so its very high quality, and the celeron 300 runs at 450 almost natrually, not much extra cooling needed at all.
-intel mobo with the celeron 400, its also a very high quality board, because its intel, but you cant hope to overclock with it at all.