How much should you spend on an engagement ring?

Poll of the Day

adjl posted...
The traditional "three months' salary" thing has some merit in that your ability to spend that much money on something frivolous is a barometer for your financial stability, and you should aim to be financially stable before committing to spending your life with somebody (whether you'll be the primary breadwinner or not). At the same time, though, actually spending three months' salary on a piece of jewellery is pretty dumb and mostly comes across as trying to demonstrate your financial stability to convince somebody to be your mate. Buy something she'll like, and only consider cost insofar as you need to for your own financial comfort. If you've been living together and sharing finances for years, you've got nothing to prove, financially speaking, so there's no point spending more money than is needed to make her happy.
I'm not really sure how well that holds up today. In the past it probably made sense since you would be taking on supporting your wife and would generally end up having kids shortly after, but now most couples are both working and already living together before they get married so it doesn't really make any major change in finances.