In some ways I liked the diamond eternity rings, I also thought it might be best to pick engagement rings design your own, which we did end up doing through a particular store. I wanted my husband to be involved in the process as well to make it special. Sometimes the man just picks the ring and sometimes the woman picks what she wants. I wanted it to be a joint process and it made it all the more special to me that the design and shape of the stone was just that, a joint effort.
I know many men will consider this holiday season as the one to propose to their ladies, my only suggestion would be to listen to what she wants and likes. Try to keep a mental note of that. Look for the best deals and try not to pay retail for a ring when you can get a beautiful ring at a great price if you do your homework!