If you're going for technical as well as power, Frazier's isn't p4p, it's way too wild. Haven't seen Tito's so I can't decide.
To the head, to me it's between Robinson, DLH, and Frazier. Robinson dropped guys with this punch more than any other I think, throwing it from the hip with crazy force and speed. DLH's was also very accurate and fast, with one-punch knockout power. Frazier's was really damaging, could wear fighters out long-term, but as seen in getting to Ali's chin by knocking him down, it packed a punch as a single blow. To the body, I'd say JCC and Cotto. I love looking at them step back and watch the bodies fold inwards crumbling before them.
No Chavez mention? He had an awesome left hook as well. From the list I would have to say. Hmm i cant really pick between Frazier and Trinidad. DLH had an awesome one as well.
As stated above, can't believe you didn't put David Tua in that list. Speaking of Lennox, I believe he's one of the few fighters that ever took a full on Left hook from Tua and wasn't rattled.
joe frazier definitely not tyson as that wasn't his primary punch he was more about combinations then just a left hook
trinidad had a great right hand too!just ask william joppy, but his hook was just real nice and heavy. I picked tyson's over fraizer's it was just way more explosive in my opinion but what fraizer did in his carrer with just the hook and a decent chin was amazing!