Well if we're talking in-game pre order bonuses, armor is acceptable. I went with the Gamestop New Vegas pre order because that came with the armored jumpsuit from Holy Vault 13, which is way more sixy than a Vault 21 jumpsuit.
That said, if it was a Vault 101 Jumpsuit I got at the beginning, I'd be "Mehhhhhhhhh..." and consider that...Not worth my pre-order money.
At the moment I can't think of any cool "outfit" type items I'd want...
Since it's based in Boston...Maybe an outfit modeled after one of George Washingtons outfits?
Oooh, or "Pre-order now, and get the Founding Fathers outfit pack. George Washington, Abe Lincoln, Thomas Jefferson, and everyone's favorite egotist, John Hancock! Gamestop- power to the players!"