upgrading engagement ring..opinions plz!

My fiancé and I are upgrading my engagement ring. The one I currently have is beautiful but it is sterling silver (not that there's anything wrong with that) and although I am upgrading, I am wanting a smaller diamond. These pictures are a few of my favorites that I can't decide between! And yes I know one of them is still sterling silver but I love it...ugh! Lol. Please give me your opinions!?