There is no "one" answer.....as it depends on where you want to fly etc..(and flying is generally the better value as opposed to gift vouchers goos etc...though recently I gained a mobile phone worth $500+ for only 10,000 points each).
Other variable include which FF Airline program you use as not all are equal...and again particular routes can be particularly good with some programs..and not so with others.
However sweeping statements (and there are lots of exceptions and if/buts)are:
* Long haul International flights provide better value than domestic flights (which are often lousy - but there are exceptions)
*Upgrades can be great value (ie say 6cents per point) BUT without status can be hard to get.
* Business Class redemptions are often next. Say 4ish cents per point.
* The RTW Onewold award at say $3000-ish for 140,000 points.
* Then long haul international domestic at say 1.5 + cents / point on some routes.
* Then domestic redemptions....
However things can change (ie Amex could change there transfer rate etc...) and it may takea few years to burn the points from this promo.....and so for aquiring tx in this promo I set a value of 1 cent per point (though I would be confident of actually redeeming at 2 to 4 cents per point).
Thnaks for your response and everybody elses.
It seems general consensis is that upgrades and long haul flights are good value.
What do you mean by 'status' when refferring to upgrading to business class?