Best weapons and armour are obtained through smithing and enchanting. You can find some decent weapons through daedric quests but you'd still get better equipment by making your own.Power levelling Smithing and EnchantingWarning: Spoiler! (Click to show)
Note. The game becomes rather easy when you power level a lot. You've been warned.
Obtain around 400 iron ingots/ores or a mixture and smelt in to iron ingots.
Obtain the same number of leather strips or buy leather/tan hides to give leather strips.
Smith as many daggers as you can.
Keep the daggers somewhere safe until you have an absorb health enchantment.
Get and fill lots of soul gems, whether you buy them or go out and kill beasts. Even petty gems with petty souls will work for this. Dewmer ruins are a good place to find soul gems and an easy soul trap method is to use a weapon enchanted with it (soul trap spell if you're a mage/archer)
Now fetch your daggers and get to an Arcane enchanter. Enchant iron daggers with absorb health using the lowest souls you have.
The initial investment is substantial, if you buy everything I think it's north of 10,000 septims. Overall though you should come away with a profit as well.
The biggest pain in the butt is moving the daggers around. I found the easiest place to do this was Whiterun; if you own Breezehome, use the Warmaidens to stock up on the initial part and then smith them outside. Store the daggers in Breezehome and go get your enchanting items ready. Once prepared, grab everything and head to the Jarls Courtwizard in Dragonsreach, who has an Arcane Enchanter. Happy enchanting.