My own thoughts, additions... from a guy who pretty much plays these games exclusively as a stealth character in a self-imposed "hardcore" mode.
All of my perk points have been spent in;
stealth
light armour
one handed (ONLY in the dual dagger branch)
archery
lockpick
I spend my stat points in 3-1 ratio (stamina to health)
Single enemies fall to either a stealthed, poisoned arrow shot at a 3X damage modifier. Use your best arrows, unless attacking a "known" lower-level enemy, mudcrabs, wolves etc. I currenly use an ebony bow with a frost damage modifier. The actual bow means nothing... it's the damage that matters.
If a first shot fails to take the enemy out... run (this is where stamina comes in) and restealth.
I have cleared entire dungeons without ever using a hand weapon.
If in close quarters, or facing tougher enemies that you KNOW will not fall to arrows, break out the dual daggers. Patience is key. I use Mehrune's Razor and the Blade of Woe right now, but again, it's a matter of what you want to use and how much damage the weapon does. If i come across rooms with more than one enemy in it... I resort to the bow. Fire an arrow down a hall, or into an empty room. They will go looking for the source. You have to act quickly, pick an enemy out of the line of sight of the others, roll into place and cut him down. Roll into the shadows and repeat. If it's simply IMPOSSIBLE to break up the group... use Shadowcloak of Nocturnal. Activate, crouch... sneak up behind the first, backstab, stand, recrouch, repeat. I have cleared entire rooms of enemies this way.
When facing really tough enemies. Poison is your friend. Dragons... giants... get your best arrow, your strongect poison, and find a good hiding place. Pick your shot and let fly... then move. Find another hidey-hole, repeat.
when all goes bad... and it will occasionally... RUN. Use that amazing stamina to your advantage. If you can't get away? Lead your enemy into another group of enemies. Leading a giant into a bandit camp is great fun.
Essential equipment? Anything that improves archery damage and backstab/sneak attack damage.
The perks are self explanatory.