And of course there's the classic round diamond in a four-prong setting:
Love! Love! Love!
I know we don't have much to go on, but if you'd like an engagement ring inspired by these, I dug up a bunch!
Engagement Ring 1: Round Diamond Engagement Ring from Ice.com, $1,395
Engagement Ring 2: __Diamond Engagement Ring and Wedding Ring Set__from Kohl's, $1,900