mkpkmp:

My spreadsheet shows the following value in descending order (with a ratio compared to a base value of 2 cents US or 3 cents per mile CAD):
 last minute Economy Class N. America (up to 4.3:1)
 N. American Business Class (3:1), last minute South America Economy Class (Varig)/W. North America last minute economy/Business Class Pacific Asia (2.9:1) or Australia last minute Economy Class/last minute European/South America Business Class (2.5:1)
 Australia Economy/Business Class to Africa (1.7:1)
 Pacific Asia/South America (Varig) (1.0-1.3:1) tickets in Economy Class

The worst value award for me is a short haul ticket in western North America with a ratio of .67:1 meaning it is worth about 2 cents/miles CAD.