I found this handy chart which lists the line diameter and length that comes with many major winches,
and lists the standard replacement line type, and then an alternate line type that will fit.


Winch Std. Cable Rope repl. Alternate rope
MileMarker 12k 3/8x100 3/8x100 n/a
MileMarker 10.5k 2 speed 3/8x100 3/8x100 n/a
MileMarker 9k 2 speed 3/8x100 3/8x100 5/16x125
MileMarker 9k 1 speed 5/16x100 5/16x100 3/8x80
MileMarker E8 3/8x100 3/8x100 5/16x125
Pierce 9000-8" 5/16x100 5/16x100 3/8x80
Pierce 9000-11" 5/16x150 5/16x150 3/8x125
Pierce 12500-8" 3/8x90 3/8x90 n/a
Pierce 12500-11" 3/8x125 3/8x125 n/a
Ramsey Platinum 95 5/16x150 5/16x150 3/8x125
Ramsey Platinum 9 5/16x150 5/16x150 3/8x125
Ramsey REP 9 5/16x95 5/16x100 3/8x80
Ramsey REP 8 5/16x95 5/16x100 3/8x80
Ramsey ProPlus 8 5/16x95 5/16x100 3/8x80
Ramsey ProPlus 6 1/4x100 1/4x100 5/16x50
Ramsey RE 12 3/8x125 3/8x125 7/16x90
Ramsey RE 8 5/16x150 5/16x150 3/8x125
Ramsey QM 9 5/16x150 5/16x150 3/8x125
Ramsey QM 8 5/16x95 5/16x100 3/8x80
Superwinch X6CD 5/16x100 5/16x100 1/4x150
Superwinch X9 5/16x100 5/16x100 3/8x80
Superwinch Husky 8 5/16x150 5/16x150 3/8x125
Superwinch Husky 10 3/8x90 3/8x90 n/a
Superwinch S9 5/16x100 5/16x100 3/8x80
Superwinch S6 5/16x100 5/16x100 1/4x150
Superwinch S45 1/4x50 1/4x50 n/a
Warn M15 7/16x90 7/16x90 3/8x125
Warn M12 3/8x125 3/8x125 7/16x90
Warn HS95/HS95i/9.5ti 5/16x125 5/16x125 3/8x100
Warn 9.5XP 5/16x100 5/16x100 3/8x80
Warn XD9/XD9i 5/16x125 5/16x125 3/8x100
Warn 8274/8274-50 5/16x150 5/16x150 3/8x125
Warn X8/X8i 5/16x100 5/16x100 3/8x80
Warn M8 5/16x100 5/16x100 3/8x80
Warn M6 5/16x80 5/16x80 1/4x175
Warm M6SDP 5/16x50 5/16x50 1/4x100

http://www.rockstomper.com/catalog/recovery/ropes.htm