I got my wife (then fiance') a 1 carat diamond solitaire for 3 grand. That was 16 years ago though. The diamond had good color and clarity but a few occlusions which lowered the price. You have to look really close to see occlusions and how often do people put their eye right up against an engamement ring.
More recently, my wife bought diamond earrings for her mother from diamonds.com We were very impressed. I believe you get a better quality diamond from them then they sell in the average jewelry store (price is about the same per carat but quality is better). If I had to by another engagement ring I'd definitely get it from there.
Good luck bro, I'm glad you found someone who makes you happy. Hope that helps. ;-)