Icebreaker BodyFit 260 Legging w/Fly - Men's

Not too thick, not too thin. They work great in a wide range of temps. Camping, skiing, climbing, they do a great job as an insulation layer, up to about the mid-40s. (I have started to run cold in my dotage...)
I am a big fan of the fly. It let's you do your business when the moment is right. Also, with the fly - and this is frequently overlooked - there is the slightest second layer of insulation for the most important below-waist terrain.
I highly recommend these.

The feel of of these Icebreaker BodyFit clothes is amazingly comfortable, soft and warm.

I tried the BodyFit 150's; these 260's are much better for me in these colder New England temperatures. I've been using them for a few weeks and have found them great for everyday.

But watch out for the sizing! I'm 5'10" and consider myself pretty average if a little slim. The sizing chart suggest size medium. But size medium was too big. I had to return them for size small. I didn't like paying for return shipping for this mistake.

Size small is working out well, though it's not a snug as I expected. Guess I need to work out much more and build up my chest, arms and legs to fill out the BodyFit.

If size small is good for average me, what size are the many people smaller than me going to wear?!

I started out using these primarily for skiing, and have since been wearing them for daily use as well. I was in Jackson two weeks ago and went from skiing to walking around town. They were completely dry, between sweating and the concrete wet spring snow. Very soft therefore they are very comfortable, the merino wool is a major plus because it is stench free. The only thing I have noticed is that the legs are a little long. I am 6'2'' and the legs are a couple inches long but that is minor, performance is much more important.

I've had an Icebreaker top and bottom for a couple years now and I love them! They really keep you warm without being bulky (I have the women's 260 weight). Plus, I wore the top for two weeks on a trek with only a thin layer underneath and it hardly smelled at all. Icebreaker long underwear can be a bit pricey, but it's a great investment. I am buying these men's bottoms for my boyfriend.