Also that one particular hagraven at that one forest east of Helgen (I think it was, can't bother to do the search), who lives at the top of that cliff, if you will, was ridiculously hard when I confronted her somewhere at level five with my first all-round Nord guy. I think she had Fireball back then, even. One full hit on me = I was dead. Had to sneak, run away, circle that cliff until she lost the sight of me, and then hit her again mainly with arrows. I remember the conclusion finally came after a careful timing. Once she noticed me, I got out of her reach behind the rock, began to load the-fire-scroll-that-does-112-damage, and unleash it JUST as she reached me and didn't get to attack me. This required about 1-2 second timing. Eventually the scroll (over)killed her off, though (she was at pretty minimal health already).
Those are some of the most epic battles. Although many group battles have been great as well, 3-5 different animals and NPCs fighting everybody against everybody. Lately I haven't really experienced any memorable battles, since I've only played that pure mage character who is invincible at level 40 (although some high-level archers can one-shot him) with 100 Destruction + the staggering Impact perk, and my thief/assassin is even higher and he cannot be seen.


) I face one of those deadly priests (who drop the priest masks) I tempt to use what ever environmental benefit.. I'm an archer at lvl 23, so I to succeed against an opponent with much health and deadly damage, I have to distance my self to get some shots. And then, hopefully, I can find a tree or a pillar to take some of the fire/frost/shock bolts 
