It's interesting, because aside from winter trips, I do much of my hiking in "temperate" areas in the western US and Canada, and I've even been to Japan and Australia.

I take essentially the same stuff. Yes, I do vary it a bit if there is a possibility for more extreme conditions, but it doesn't change a heck of a lot three season - a synthetic layer to hike in, a wind/rain shell, a set of poly long johns to warm up and sleep in, and some insulating layers - couple of merino shirts, a fleece or primaloft jacket. hat, toque, gloves, etc.

Then either a hammock with underpad/poncho or tent and little pad..

and my sleeping bag - I *will* take a warmer sleeping bag if conditions warrant, but my light (-3C rated) MEC merlin goes with me most of the time these days.

That goes with me from coastal rain forest to high alpine, all over the west, and from 54 north to 43 south in lattude, Canada, USA, Australia, and Japan.

Now admittedly I've done nothing overnight in true desert conditions, have to do that someday, and the warm deep south I've never done more than day trips in. But I find it fascinating how *little* my gear changes for three season trips.