Having fun on Master with a master thief type build. No armor skills, mostly not killing people (some quests don't leave me the choice but I did finish the thief's guild quests not killing stuff if possible). Everything done through stealth and pickpocketing. Falmers get to feel the wrath of my dual elven dagger (Fine) 15x backstab power though cause they are mean

Mostly, doing the thief's guild quests in a "thieves don't need to kill" way isn't that easy until you get your skill to 90+ which was fun. Some bow+arrow distracting power helped

Oh and Pickpocket success rate caps at 90% but if you don't push it too much, you can avoid fighting the people that catch yo. But you'll get a bounty in the process which is fun to live with

Guards are all "Hey, I know you" "/me moves away quickly" and when I'm bored I talk to them like "Yeah sorry, I cannot pay that 25 bounty, I only got 40k gold so send me in prison cause I didn't try to escape from this one yet"
PS : when you want to flee from a prison, the lockpicking perks are actually VERY useful.