Wow that's a tough one.
1. Lying short bar tricep extension (I made this up by putting the weights in the middle of an 18" bar, holding it reverse on the ends, and then lowering it over my head and then back up straight over my face) Love this one.
2. Strap tri pull downs kneeling
3. Dbl db row bent over 90Deg, head on a bar
I guess those are the top 3 but there are more and they are all pretty close in terms of favorites. I don't do anything that I don't thoroughly enjoy. Maybe that's why.