I absolutely adore this villainess!  What a career!  Madame Hydra once upon a time, leader of the Serpent Squad (and usurper of the Serpent Society), a twisted affair with the Red Skull (remember him letting her torture him for pleasure?), White Princess of the Hellfire Club, ruler of Madripoor, bride of Wolverine (and brain-washer of some damned powerful X-ladies!), conflicts with Cap, Spider-Woman, the X-Men, the Avengers... what HASN'T she done?

I would have to agree on that. I adore her also, in everything she has done. She is an awesome villainess. I honestly don't know who couldn't like her.

I dunno, in Captain America #342, Black Mamba makes the point that Viper loves no one or nothing- not even herself presumably(after trying to probe her mind to select an image of someone she loves or trusts). Still, she was willing to fiance and arm the Punisher(presumably to destroy her enemies)!
 
Terry

I love the character Viper. She was one of Captain America's greatest villains, sadly not the character has been hijacked more and more into being a X-men/Wolverine villain. She was always a portrayed best as a crazy psychopath with zero regard for innocent lives. I love it how back in the day the would only show one side of her face. It gave the character a certain mystique, sadly that is gone and now you see her full face all the time. 
 
I would love to she her play a big role once again. She really is awesome a a psychotic terrorist. I prefer her on her own rather than working with Hydra. She should be a big time Marvel A-list villain.