I love Patagonia clothes, and religiously attend the holiday sales at the Dillon, MT outlet. For winter clothes I usually shop for things to wear skiing (you put in on and leave it on) as opposed to backpacking (you're carrying a pack, so mix and match as needed), but these items are what I like:
Any and all wool underwear. Patagonia's merino stuff is top-notch, bested only perhaps by Icebreaker. Wool 4 is exceptionally warm and soft.
The heavyweight wool socks are rarely found, but they're the best that exist (I think they call them expedition weight, with a retail price of $35 or more).
The Dimension Jacket for all day winter wear. Heavy, but the best recreation of the classic Sierra Designs 60/40 parka around. They might have some in the "ranger green" color that Patagonia made for a military contract. Dimension pants are very rare, but I love them.
Of the synthetics, I like the R1 and R2 fleece. R1 pants are great for "real cold" underwear, and the R2 fleece jacket is probably, with the Mountain Hardwear Monkey Phur, the best fleece ever made. Of course, fleece doesn't match up to down for winter "warm up quick" use, but if you have to wear something warm all day long, fleece is greatly preferable to down or synthetic puff insulation for breathability. R1 pullovoers are a staple of my winter wear, and the new R1 full zip has quickly become a favorite.
The DAS parka is heavy and not all that warm, but tough and certainly weather-resistant. I like mine for mucking about when it's 30 degrees and the snow is falling like dinner plates.
Capilene 1 is silky smooth, and might do for all day wear in the Sierra, but it snags easily and has a quick flash point for cooling.
The Ascensionist jacket lies in the middle ground: not that light, not that tough, but it has become one of my favorites for winter wear (again, I'm talking about a jacket you wear all day).
Almost all of the Patagonia guide pants are great, although the Alpine Guides with their built-in gaiters and suspenders might be overkill for what you want. I'd stay away from the Simple Guide Pants and others that either don't have belt loops or a fly zip--the drawstring waist adjustment doesn't work all that well.
The Stretch Element Jacket is frightfully expensive at full retail, but it is a beautifully-made hard shell parka that is surprisingly breathable considering it doesn't carry the eVent or Gore Pro-Shell label.
The Houdini wind shirts/jackets are justifiably acclaimed.
I like the softshell/fleece combos (such as the Winter Guide series), but they're probably too warm/heavy for winter backpacking in the Sierra.
Although they have incredibly fragile shell fabric, you'll find it hard to beat the warmth/weight ratio of the Patagonia Down Parka.