Of the ones you posted, I like the first and third. You will need to be tall to pull off the first one.

On the other hand, I have recently purchased a few non-maternity new look cardigans. Unless you want to be able to close the cardigan, there is really no reason to purchase maternity. I think they generally look better open anyway (unless it's a wrap cardigan with a tie) because buttons are bound to pull over an expanding belly. Plus you'll be able to wear non-maternity styles next year too.

I really like the first cardigan, however I'm with Patience if you can wear non maternity go for it.