<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Statistician:
I strongly feel that you can only place a value on your points that's up to the amount you WOULD HAVE OTHERWISE PAID, not the value the airline would have charged you.
I have to ask... If you had no miles and wanted to take that trip, would you have gone in FC or Coach?
</font>
While that makes perfectly logical sense, what about the trip which you would NEVER have taken if you had to pay for it?
Are the miles priceless or worthless in this instance?
There could be an economic argument that you would have eventually saved the money to go, but I'm thinking of, for instance, a business traveller who has accumulated enough miles by commuting/consulting/whatever that he/she can fly a RTW, for instance. They may have never even thought about paying the equivalent value for such a trip, but can go because of the miles.
I think valuing miles is totally internal, and only an individual can really decide their "comfort level" based on what they want to do with them and how they are earning them.