the answer to this question is always which colour best matches your room! If your room has white carpets and a green couchs I'd go with the any flavour of the blue bios, but if your room has red carpets I may try the silver or yellow, but then again, if you've painted your xbox and not taken your room colours into consideration then maybe just go with the color you painted your xbox.
Seriously though, is it that hard to read more about the bios' you've d/l and know nothing about? All the 4976.02 are the most up to date executer bios' and they have the media flag check right in them (I can see another question coming here) so that would probably be your best bet, the evox bios' are little dated now but if you want to run an all evox box go for it, especially if the evox.d.6.blue brings out the colour of your eyes.