I know they are not the cheapest gaiters, but I have these:
gaiters and they are absolutely wonderful, very well made and snow-proof. I got the large because of my big size 9 winter boots.
I have waterproof rain pants I have worn snowshoeing, but I find I get too hot in them with tights underneath.
Instead, I wear a pair of UnderArmour winter tights, then some Ibex wool tights over that,and the gaiters, with my heavy wool socks and winter hiking boots.
With that outfit, my legs can still 'breathe' and I stay warm but don't get sweaty.
We are talking temps down to about 20 I guess, with no strong winds or freezing wet slush.
I find ANY jacket to be too hot after snowshoeing along for a while. So I wear a couple of thin wool base layers, maybe an Ibex merino Shak top if it's really cold, good double gloves, a wool hat or a thin silky balaclava, and then just a warm wool vest. Again, you can see this type of outfit I've described in my signature snowshoeing photo below....minus the gloves which I took off while we were fiddling with the camera.

This type of layering keeps me warm but prevents me from getting all sweaty.
I have no experience in XC skiing, so I don't know if there are different needs involved with that. But I'm sure some of the clothing needs must overlap with snowshoeing clothes somehow.