A setting I LOVE for rounds (yet didn't think I would) is the U-Prong Champaigne Pave by WF. Although not a round, see this link to get a better idea of the setting:
I like #1 or #2. #1 is more classic, #2 has a little extra design to it. But the practical difference is how high the stone sets. Higher will make is stand out more, but be less practical if she is active with her hands. It becomes a personal preference.
If this is for the .5 carat round brilliant in the previous post, then I go with #3...I think the width of the band, accompanied by the little something extra of the surprise diamond- without being too overpowering is the best bet of the choices.
Thank you for your opinions and it helps a lot. So if i could go to a .59 with the 4 prong tiffany or a .49 with the surprise diamond which one would you ladies choose? THE BIGGER DIAMOND WITH THE 4PRONG TIFF OR THE SMALLER DIAMOND SET IN A NICE UNIQUE BAND???