When I was around the teens in levels, I mostly just did my best to avoid spriggans, bears, and will o' the wisps. Then, I hit 50 Destruction and made some spells that made short work of just about any enemy in the game. (Think elemental damage + weakness to magic + weakness to given element, used by touching a few times in a few seconds. Made a variant with a second of paralyze once I hit 75 Destruction. No enemy is hard with this.)
Now, though, I am wearing gear that makes me faster, and using a spell that boosts my speed every few seconds, so I just run past most enemies unless they would fill a nice soul gem for me. (If my character had a bumper sticker, it would be "I break for Minotaur Lords.") I stopped going into random caves and mines because I'm not very interested in wonton slaying without a quest to frame it anymore. It was kind of getting repetitive, and there are certainly more than enough hours of quests to keep me busy.
On my vampire character there aren't many mobs that are set to be aggressive. Most wildlife will leave her alone as long as a weapon isn't drawn. All undead except liches (nether liches are cool) are considered friendly.
That being said whenever I run across an ogre or minotaur I have a good 2-3 minute fight on my hands. Doesn't matter how you fight them. Their only purpose in life is to tear **** up.
Is that a mod, or is that a natural aspect of playing a vampire? That sounds awesome.