jelly roll pan but didn't have one. I died a little because my cookie sheets (they're standard half sheet pans aka jelly roll pans and measure 13 x 18) are one of my favorite kitchen tools. I use mine for cookies, brownies, cinnamon rolls, roasted veggies, chicken, even cupcakes (I always put a pan under the muffin tin to help keep the bottoms from getting too browned). I also use these to carry home dinner, loaves of bread (I usually make about 10 at a time in my Bosch and freeze the rest) or even craft projects when I've been working at my mom's house. The little lip on the side keeps things from tumbling out and they are easy to carry, stack, and use all the time.
I saw my favorite cookie sheets are available at Costco right now and snapped a picture to encourage you to run and buy some if you don't have them (or get them at Amazon of course). The two pack of NordicWare baking sheets is only $11.99. That's $6 each people! I can tell you from experience the one time I saw one of these pans (used) at the thrift store it was $5 (and I bought it).
When I was newlywed I foolishly thought there might be such a thing as too many cookie sheets but have since repented of such crazy talk. To be fair, I didn't make hundreds of cookies or cupcakes back then like I do now. So I say the more the merrier with these handy pans. Barefoot Contessa has a huge stack in her pantry I covet every time I see it.
I've also slowly built up my Silpat collection and now have one for each of my pans (along with a plastic lid- they're so handy). You can read more about Silpats here. I do not miss greasing my pans or scrubby out gunky pans one bit. Costco also has a three pack of knock off silpats (silicone baking mats). Has anyone tried them? I was kind of dying to buy them just to see how they were. Amazon has a 2 pack of generics for $16 as well. Please let me know if you've used them!