Dirty Harry vs Deathwish vs Taxi Driver

That's a very well thought up list, since all deal with one character predominantly dealing with terror and a social acceptance of terror in some way.

From bottom up:
3. Taxi Driver. Just not very interesting. Some good lines, but boring characters and ranks last in credible motivation among these three, although the motivation is still more credible than most modern day movies. 4/10

2. Dirty Harry. Harry is over the top on self righteousness and bigotry. However, he has a policy of "innocent victims are innocent victims and guilty terrorists are guilty terrorists" is strikingly realistic, and something that still today most people have problems with. No terrorist is a "freedom fighter" to anyone. People who claim so are liars and totally out of control to demons. Harry had a handle on this. 8/10

1. Death Wish is clearly the best in terms of the lead character. He slowly evolves into vigilantism. He begins totally meek and calm, ready to play by the rules. When he has full reason to turn vigilante, he doesn't go right out and start shooting. He loads a sock with coins in order to provide a defense, and tests himself. 8/10

1. Death Wish - 9/10
2. Taxi Driver - 9/10
3. Dirty Harry - 8/10

Taxi Driver
Death Wish
Dirty Harry

Dirty Harry
Taxi Driver
Death Wish

1. Dirty Harry (due to the villain)
2. Death Wish

I haven't seen Taxi Driver in years and it requires a re-watch at this stage.

I saw Taxi Driver dozens of times when I was young but prefer the other two now. I guess I find DeNiro to be the least endearing of the three leads. Like DeNiro, Taxi Driver may be technically more proficient but less enjoyable.

All three films have excellent soundtracks and authentic settings and hit all of the right notes regarding sleaze and violence.