Leon for sure, though I like him less with each installment. The characterization from RE2 was a very refreshing, believable take on a male protagonist. He was noble, well intentioned, and brave..but he was also scared, idealistic, naive, and a bit frazzled. He wasn't the archetype of a hero - he was a very flawed person trying to live up to that archetype as best he could in a situation in which he was completely out of his depth. I also love the initial character design and color scheme.
Later Leon as the suave, brooding, wisecracking ladies man is, frankly, kind of lame, imo. He's still my favorite because I cast my lot with him in 1998 and won't jump ship, but it's definitely not really in keeping with what I liked about him in the first place.
I find that most of the flaws that plague more modern interpretations of Leon also apply to Chris in general and, to a similar degree, also pervade Jill and Claire's more current characterizations. As someone who liked Jill in the original RE and RE3, the characterization in the Nemesis remake was pretty nauseating. The need to have her be over the top in her self-assuredness and indomitability was grating and they seemed to think that she became cooler with every utterance of the word "****." The remake Claire was similar in this respect, albeit slightly less over the top. In both cases, I feel like the shift to make the characters bigger "badasses" actually made them feel more homogenized and trite, to the point that you could've easily swapped out one for the other and - in terms of characterization and dialogue - noticed virtually no difference. I'm cool with badassness to some degree and get why it's appealing on some level, but if the net effect (via cliched execution) is to strip characters of their individuality, then it's almost the opposite of empowering. It becomes a form of erasure by virtue of subsumption into a set of stock characteristics that send some sort of message about strength, but do so at the expense of relatable humanity and unique psychology.
I think that's an issue with literally every character on this list at this point. You almost have to look to the peripheral figures in these games to find someone who's not an overblown model of in your face attitude. I suspect that's an issue that plagues many other video games, but I admittedly don't play enough to know. Either way, I wish RE would dial it back a bit. The characters were much more likable in the first few games when they were allowed to show weakness, vulnerability, uncertainty, and coping mechanisms outside of shooting stuff whilst wisecracking.