DS9 needs to come first, because frankly, if given the chance, I think it would get buried and forgotten otherwise. DS9 has always been the red-headed bastard step-child of Trek, despite being the best series. And we've seen what happens when you piss off the Niners: or do we forget that early Enterprise promo where they omitted Sisko and the uproar that garnered?
Do DS9 first. Or hell, alternate - DS9 season 1, Voyager season 1. Back and forth. Whatever it takes. Just give us DS9 in HD. I'll willingly pay $80 a season for that. Again (did on DVD... )