You can look at it by plane type:

1. On a domestic flight:
- 777 and 767-200 have three-class cabins, so they have a 'real' first class;
- 767-300s have a two-class cabin, the front cabin (60" pitch) is considered first class; and
- 757s, 737s, A300s, and MD80s have two-class cabins, the front class is considered first class, but the seat is inferior (37-39" pitch).

The front class of the two-class cabins can be booked with a DONE as well as an AONE.

2. On an international flight:
- If you're going to anyplace else in North America, including the Carribean and parts of Central America, the "first" class cabin in a two-class configuration is now called "business" class.
- 757 flights to Manchester are considered all-coach
- 777 front cabins are true "first class"
- 757 front cabins to South America, those I'm not sure about.