MLD Zip - It's been replaced by the more durable Exodus, but my first generation Zip was tough enough to function as my day and overnight pack for a full season of on- and off-trail guiding in Denali National Park and come out looking good as new. Light, tough, simple.
Mont-Bell Peak Shell - At 11oz, it's far from the lightest jacket out there, but the combination of breathability, features (really nice hood, hand pockets, big pit zips), and durability made it the perfect choice for a wet Alaskan summer. I practically lived in this jacket, including 5 weeks of solid rain spent slogging through blueberry bushes, willows, and mountain alders, and there's not a hole to be seen.
RailRiders Weatherpants - Indestructible. Just as perfect guiding in Denali as doing sub-zero WFR scenarios in the Tetons (with a set of Patagonia R1 Bottoms underneath), these pants are comfortable, cool/warm as needed, quick drying, very wind resistant, and bomber. Despite a lot of abuse, they still look brand new.
Other gear of note
Patagonia R2 Jacket - My go-to fleece. Supremely breathable on the move means that wind cuts right through, but throw on the rain jacket or wind shell that you're always carrying anyway, and you're quite toasty.
Patagonia R1 Hoody - My second skin. Breathable, warm, built-in head and hand warmth, long waist, and tough. If it stays below 50F for the day, this is it.
Backpacking Light Cocoon UL 60 Hoody and Pants - For the volume of a medium stuff sack and a total weight of 17 ounces, you get an insurance policy against being cold. These were especially wonderful to have above the Arctic Circle in late September; they kept me warm standing around camp and easily pushed my 32F bag into the teens.
Western Mountaineering Summerlite - For 19 ounces and a teeny stuffsack, I'm comfortable from freezing on up. The hood and full-zip let me use it as a quilt, hatches-battened bag, and everything inbetween. Combined with my Cocoon clothing, it's a solid three-season bag.
Books - Sibley's Field Guide to the Birds of Western North America, Wildflowers of Denali National Park, Dena'ina Plant Lore, Discovering Wild Plants, Kantishna, and so much more. The more you put into the world around you, the more you receive. Learning about where I was and carrying that weightless knowledge into the backcountry added to all my experiences in untold ways.