Depends on the character I'm playing as. Considering that I play as vampires only, with the exception of my hunter Harker, the "good" factor is strongly and utterly based on perception.
Vlad is just a brute of a vampire. He'll take on any challenge, good or bad, day or night, as long as it's for what he believes in.
Iandir is, in my RP, a High Elf sent by the Thalmor to eliminate the Emperor at any cost. He was made into a vampire to increase his chances of survival and his insured continuation if he was to meet an unexpected end. He kills all enemies of the Thalmor.
Harker is my only human character. He is a hunter. He hates wolfs, in any form. He kills animals for profit and has killed a werewolf as well. Wears it's hide as a trophy.
And lastly there is Mina. Oh my Mina. She is my favorite and most deadliest character. Dubbed the Dark Lord of Skyrim, she is a vampire who just wants to see the world in flames. Twisted and evil, she commands an Army of the Dead, Dremora Lords, Antioch's, followers and a group of mages that guards her fortress (College of Winterhold). She kills everything in her path.