Just jumped in on this post. Flagpole is about 98% right on what he has been saying (I leave the 2% margin of error for my possible misses due to quick skimming).
A ring really shouldn't have to do much with how much a person makes. It is 100% a luxury item--a symbol (created by the diamond industry--kind of like Valentine's Day was created by a card company). It has no practical purpose whatsoever.
I'm working my first "real" job right now, but have worked in one form or another my entire life. I'm single, and making more than enough to live extravagently--although still making far less than Flagpole or xcgirl--but I'm saving already and have a plan for retirement. It's the extra spending on the things that don't really matter that can kill people. Things that people decide they "need" based on marketing or whatever other stupid ideas they have in their head. I don't care if you are Bill Gates. Spending $20,000 on a symbol is just plan silly.
Currently dating a girl with a similar attitude to my own, and I'm crazy about her. I think she would be insulted if I spent even 25% of that amount on a ring because it would be too much. I know she would rather spend the money on a vacation or to give to charity (or maybe a bit of both).
Cheers!