Most professional baking pans are either aluminum or aluminized steel. Stainless steel pans are sometimes used, but food sticks to them like you wouldn't believe. Silicon mats, acetate sheets and parchment, are usually used to line the pan anyways to further prevent sticking.
The best baking tools really depends on what you're planning on baking. For cookies, I couldn't live without my stand mixer and silicone baking mats.
Things I can't do without:
mixing bowls (1 works, 2+ is better) Rubber spatula 9x13 cake pan measuring cup/spoon set hand mixer baking tray(s) silicon mats or parchment paper cooling rack(s) Food scale (Oxo): May seem superfluous but I highly recommend you get a scale! Ensures your measurements are always consistent. Instead of dealing with measuring cups, you can just scoop ingredients into a bowl. Scoop, measure, tare, repeat. Really speeds up prep too. Pyrex pie plate 13" x 9" cake pan (I generally like USA Pan brand cake pans) 8" x 8" square cake pan (USA Pan) 8" or 9" round cake pan (USA Pan) Loaf pan (USA Pan) Cupcake/muffin pan (Wilton Avanti) Springform pan (Chicago Metallic) Tart pan (Chicago Metallic) Wire whisks Offset spatula (Wilton) Rubber spatulas (Rubbermaid) Smaller bowls for prepping ingredients Even more bowls for other stuff (are you getting the picture yet) Dough/bench scraper (I like flexible ones) Rolling pin Portion scoops of various sizes Stand mixer if you can afford it. Otherwise, a hand mixer. But there are some recipes you will just not be able to try. Wire cooling racks that fit inside your sheet pans (at least 2)