16 to 20 depending on terrain

I like to hang treestands as low as I can while still having some cover around me.  

The height varies alot from tree to tree and with terrain type.  

I've been as low as 10 feet in the early season and as high as 35 feet when hunting river bottoms with straight pole timber in late season.  

I'm a little scared of heights but a treestand has never bothered me.

Regardless of how high you hunt, do yourself and your loved ones a favor and wear the very best fall restraint system you can afford and if you cant afford a good one borrow money.  If you hang around in trees long enough you are goping to have a mishap.  Be prepared for that day.  Okay enough soapbox.

Trap

I'm not to keen on Two screamers I like to scream one time before I hit the ground.    15 to 20 ft.

Right around 15-23'.  Lower I'm exposed, higher and I loose all my shooting lanes and can't see them coming in.

In the swamps it varies from 8-14', just out of the scrub, but not high enough to stick out.

20 to 25ft. I'll cut my shooting lanes while im in the stand and directing a friend to cut what needs to be cut from the ground.

I have gone lower in recent years.
For hogs, I like 8-10 feet. Deer hunting I go as low as I can get away with(usually 10-12').As long as I have good background cover I feel that's high enough and not so high I won't hit both lungs.
I've been hunting a lot more on the ground lately, to me that's the ultimate.

I usually set the platform at 20ft for deer.Lower and the wind has to be strong and steady to get away with it around here.In late season when the woods are thin I might go a bit higher and have hunted at 30ft in the right location.I hunt on the ground for hogs.

I like to be able to reach up and touch the platform with an arrow from the ground.

My ladder stand only reaches 12'.

12-15' for me.  Like Huntrdfk, I use 3 LW climbing sticks.

15' max when hunting with my kids
18'-22' on average for whitetail depending on cover and terrain

The lowest possible cover between 0-12'.

Though I prefer the shot angle from the ground.