A legendary daedric bow is the only way to go, really, even in close quarters. I can one shot most anything short of giants, dragons and high-level vampires/chiefs - and sometimes even them if I pull off a sneak attack with a crit to the head. I enchanted it to paralyze, too, so if that first shot doesn't drop them, they can't react before I get off a second. Dawnstar and Nightingale Blade work great as dual weapons if I'm feeling like jumping in hand-to-hand, too.