I mostly backcountry ski or ice climb. I'll wear basically the same thing for both.
I generally run too hot for hardshells opting instead for softshells, mid to weight((Arc'teryx Psiphon AR). Sometimes if the snow is really wet I'll wear Neoshell half bib pants that work really well. I generally like high waisted bibs. Keeps the wind and snow out. Normally I'll wear a base layer like MEC T2 or merino 200gm/s weather dependent.
I've tried a few other things like Fjallraven Kebs (weird seams, and poor water resistance), Gore-tex Active Pants (Not breathable), but Psiphon and NeoGuide have been my favoured system for a couple years now.