Veronica.
Felicia Day is a nice person, but I HATE THAT CHARACTER SHE IS SO @#%^! ANNOYING, AND DIES IF A MOLE RAT FARTS IN HER GENERAL DIRECTION.
Also, the most annoying person in the game so far that I've had the displeasure of speaking to would be... Fantastic. Hands down.
I LOVE Veronica, SO MUCH. She's one of my favorite video game companions ever. "Holy Hell, that's a lot of energy weapons" was the cutest, funniest line I've ever heard.
And Fantastic's "theoretical degree in physics" made up for his annoying "dude"-ishness.
The only character that has annoyed me to the point of irrational violence was Ranger Milo.