Jelly Roll Pans, a.k.a Commercial Grade Half-Sheet Pans.
I really lucked out having a MIL who is a caterer. Because, I have received many wonderful kitchen items from her. I think I have about 8 of these...for catering jobs, and Christmas cookie season. But, one or two, for the average kitchen is sufficient.
Because they are commercial quality they won't warp under high heat, like most cookie sheets will. The edges make it ideal for making sheet cakes, or keeping liquids from leaking when roasting veggies, or meats.
You'll see mine in many of my food photographs, because I use them constantly. Go get one!