1/8" on my commuter, 3/32" on my Leader 725 and Switch. Mostly dictated by the components I bought for them and wanting to match tolerances. I think durability is negligible between the two if it's just for recreational rides or urban commuting.

My Switch frame is 'sorta' a weight weenie build and 3/32" chain is lighter by a fair number of grams (by weenie standards).