Re: Would you ever skip newborn size?
If it is a matter of having strict limitations on budget and needing to really stretch your pennies, I would understand skipping newborn size. Although I would still encourage considering getting some flats so that you can get a good fit anyway.
If you can afford it, it is really nice to have newborn size diapers. Those early days are such a whirlwind of frequent changes and it is really nice to have something that fits well on those tiny little legs, under the cord, etc.
My DD was 8 1/2 lbs at birth and outgrew her NB stuff around 5 weeks. I used GMD prefolds and a variety of covers. I still use 6 of the prefolds as burp cloths and big wipies, my baby is 8.5 months old. I am saving the stash for future babies.