Lots of good advice here. I'll add mine.
1. 100% agree with those saying to go for size over clarity, color, etc. All those things are just a distraction and selling tool. Maybe once or twice in my life have I ever looked at someones ring and said 'Oh, that has nice sparkle'...and it is most likely because it is big and high quality.
2. My wife's ring at this point is an accessory...an everyday item. Perhaps it has some sentimental value, but after a few days, it is just a ring. She will be more impressed...and more importantly her friends and family will be more impressed...if it is bigger rather than shinier. At the same time, I've seen some embarrassingly small and cheap rings that people say nice things about...so any ring will do to some extent.
3. As far as price, I would spend what you are comfortable with and maybe an extra grand. I've been married 11 years and looking back, I wish I had spent a few more bucks on the ring to get her something a little nicer. I would say the same with the wedding. It is a stupid, frivolous purchase, and a total rip-off, but it is one of the few things that lasts through your marriage. Assuming you have a reasonable career path, spend a few dollars more than you think you should.