My luxury item is a really cushy bed. I start with the MSR Zoid 1 tent (only about 5 ounces heavier than the Salathe bivy and Granite Gear White Lightning tarp it replaced - both of which were also somewhat toward the luxury end.) I put my empty Vapor Trail pack (perhaps another luxury in itself?) in the foot end of the tent (hipbelt up and at the very foot), then put my Prolite 3 short pad so it butts up against the pad. (Yep, another luxury.) At the head of the tent, I place my hiking shoes. Then I inflate my MSR Dromlite with air (unless it's already filled with water), and lay it on top of the shoes for a pillow. (If I'm carrying a fleece top, and not wearing it to bed, I'll wrap it around the Dromlite.) I now have an incredibly comfortable bed, even on the rock ledges I frequently choose as campsites.
For what it's worth, my warm-weather base load is about 12 pounds, which means I leave the trailhead for a warm-weather, long-weekend trip carrying about 16 or 17 pounds; a cold-weather, 4-night trip gets me up to about 20 - 22 pounds.