Well, given that "The Gauntlet" arc of Amazing Spider-man finally arrived to Mexico, I have to say it:
Electro from "Power to the People", written by Mark Waid with art from Paul Azaceta.
Electro has always been one of my favorite members of Spiderman's rogues gallery. Despite the fact that he has always been quite one dimensional, he can be a really deadly foe when written well. In this story Mark Waid not only managed to portray him as cunning and dangerous, but for once actually gave him some sense of pathos. Granted, Max Dillon is still the same opportunistic loser that he has always been, but for once he actually has some lofty goals (loftier than what he usually does at least) and employs imaginative methods to achieve them.
On a somewhat related note, I'm liking the concept behind the current incarnation of Venom. IMO, Venom started as one of Spiderman's more compelling enemies, but as time passed, he just became a joke (and changing the host of the symbiote from Eddie Brock to Mac Gargan didn't improve things in any way). I was not particularly interested when the new series was announced, until they revealed that Flash Thompson was going to be the new host.
While Flash has never been one of my favorite characters, after what happened to him in recent years I was genuinely interested in how the writers were going to develop him from there. Having Venom as a black ops operative for the U.S. goverment didn't really appeal to me. But having as the host for the alien a man that not only was crippled while serving his country, but that also idolizes Spiderman, and that actually has good intentions despite the fact that his bully persona makes him an easy target for the dark influence of the suit... Well, that's just a great recipe for drama, adventure and suspense.
From what I have read, the writter (Rick Remender) has not only realized the potential of the concept, but has finally given some respect to the character and turned him into a genuine dark reflection of Spiderman. I just hope for the book to be published in my country and sooner rather than later.