I'm laughing at all you people with your archery and sneaking skills who can't kill a bunny rabbit.
Currently playing on master difficulty. Hardly ever die. Elder dragons die in basically 4 hits (tougher than a frost dragon). I only have problems when I get ambushed by shock mages.
Currently level 43, finished thieves guild, dark brotherhood and the college quests.
Seriously though... Forget stealth and all that crap. Your class makes hardly any difference save for your unique power (which I've never used).
My build currently is:
Conjuration - 100. Nearly all the perks (Best skill tree by far)
Smithing - 100. Nearly all the perks
Enchanting - 70. Nearly all the perks
One handed - 94. Damage perks
Heavy armour - 60 odd. Juggernaut perk only
Everything else is conincidental and pretty useless to me (apart from lockpicking - was useful for the thieves guild quests)
I started with the intention of building a battlemage, so I went for destruction... What a joke of a skill tree. It rapes magicka and does little to no damage (let alone the fact that you miss more often than not).
I used bound sword to max conjuration ASAP and the front atronach until level 75, then I got summon dremora lord. Once conjuration is lvl 100 i upgraded the twin perk so i could summon 2 dremora lords.
I maxed smithing asap to build and improve heavy armour (currently in a full daedric heaby armour setup - with a daedric shield and one handed sword)
How I play: I see baddies, I summon 2 dremora lords, everything dies in 3 seconds. If they run at me - I swing my sword and they die just as quickly.
As for dragons (considering the dremora lords can't attack them in the air) - I summon 2 storm atronachs, they pew the dragon until it lands, I hit the dragon a few times with a legendary daedric one handed sword and it dies. Now that I have the dragonrend shout, it's gotten way too easy.
I still haven't shot a single arrow.
*spoiler alert*
Also, someone mention why buy a house. Well, you need one to initiate the dark brotherhood quests.