My 4 Mirro cookie sheets and my huge rolls of parchment paper.
I've had my Mirro cookie sheets for about 30 years. The larger sheets are 14x17, the smaller are 12x15. The Kirkland brand (Costco) parchment fits perfectly each way for these sheets. What do I love about these particular cookie sheets? First, they are made of heavy aluminum, so you don't hear them warping in the oven. Second, they have flat sides with no lip so no trimming of parchment paper needed. Third, they are angled at both ends so you can grab them easier. I wouldn't trade them if someone were to offer me a hundred bucks. Also, I just did some digging and it looks like Mirro ceased to exist in 2003. Come to think of it, I think my pressure cooker was a Mirro. But, what I also found, for any of you who are interested, is that Amazon.com sells a similar cookie sheet that was also recommended by America's Test Kitchen. It's a Vollrath 68085 Wear Ever Aluminum 17 7/8x14 cookie sheet and sells for $31.00. Yes, I know that isn't exactly cheap, but what's the saying, "you get what you pay for." And the reviews on Amazon are glowing.
My kingdom for Kirkland brand parchment paper. I usually buy four rolls at a time. I absolutely LOVE the stuff. If you bake a fair amount, you will appreciate this huge roll, and the fact that it also has a cutter, and the fact that it's not folded in a package. Not only do I use it for baking cookies, I roast vegetables on it, toast nuts on it, make granola on it and steam fish in the oven with it. The burning point is also fairly high. I can't really think of anything else, but for the fact that I LOVE IT!!!