I play a sneaky assassin type and I use magic, alteration magic, as the detect life/dead is an absolute necessity.
There's also the Aura Whisper shout which functions much like the Detect Life in Oblivion (even at level 53, I have yet to see Detect Life/Undead spells in Skyrim, presumably because my Alteration skill is too low, so I can't say how it compares to them). And, yes, I make very heavy use of it.
The one thing I will ask about anyone who is intending to play over lvl 50 is how do you do it exactly?
I just play the same as I always have, pretty much. I've picked up a few new tricks here and there - Quiet Casting summon spells, dagger backstabs instead of purely sniping, etc. - which coincidentally involve new skills, but it's because they work for me, not because I'm deliberately trying to force my level higher.
In effect, you have to drop your char build say for instance a 1-handed light armor, for a 2 handed heavy armored toon. Considering that after a certain lvl, points are much harder/take longer to attain, the creatures in game have lvlled up and you are using skills that are pretty low so you aren't hitting hard with your 2 hand or getting protection from your heavy armor, how do you actually survive without dropping the difficulty lvl. The lvlling system seems rather counter-productive to me if you intend to max out your char.
You're forgetting that areas "lock-in" based on your level when you first go there. Even though I'm level 50+, when I pass through the Riverwood/Windrun area, I still run into groups of level 1 bandits led by a level 6 bandit chief. (My last pass through there, I ran into two groups of bandits, one at a camp, the other passing on a nearby road. I ambushed the road group and the camp group came running when they heard the fight. I was spinning around with my bow, one-shotting everything in sight even after getting spotted - I thought I was some kind of super-ninja or something. Then I got curious and used the console to check their stats and see just how awesome I was... I would have been happier not knowing.) Wolves are still everywhere in the wilderness, too - it seems that wildlife encounters only add new creatures as you level without taking away the old ones.
Personally, I'm not concerned with "maxing out" or further inflating my level, but I am still going up slowly because Sneak is my only main skill that's hit 100 yet - Lockpicking is 93, Archery is in the low 80s, Speech is around 70, One-Handed and Light Armor are lower than that. Still plenty of room to advance in things I've been using all along. If I wanted to "max out" and push for 81, though, there are plenty of low-level enemies running around certain parts of the world where I could just pick up a crappy iron greatsword and grind Two-Handed or drop a weight on my right mouse button, then go watch TV for an hour or two while they beat on me to level Block and Heavy Armor. (What, you think a wolf or skeever will even dent my health if I'm dressed in full Legendary Dragonplate and blocking?)