There are no 'best' or 'worst' seats onboard aircraft
Darrens advice on this site is always excellent and very welcome.
However, one disagreement.
Following my flight to Cancun on one of the Ex-FCA 767s last month, I DO believe there is definately a "worst" seat row.
Row 19 - just in front of the emergency exit on these planes does NOT recline. However row 18 in front of you DOES recline.
So if you get one of the "inconsiderate recliner" passengers in front of you who zonks their seat fully back at takeoff and keeps it there till landing, you have virtually no personal space, the headrest in front of you and the persons hair in your face, and a personal video screen you can hardly watch.
Surely nobody could suggest this is pleasant for nearly 11 hours!
So I recommend everyone AVOID row 19 on Ex-FCA 767's.