I love the baking sheets sold at Sam's Club. They are their own private label but they are full size with NO non stick coating. They are made of a material that won't rust so they will last forever.
I do own a few Silpats but I am really not a fan of them. (Another nice thing about the Sam's baking sheets is that the Silpats will fit on them. Otherwise the Sipats are too large for other baking sheets.) I prefer to use nonstick cooking spray.
As for meauring cups, I think you must have at least 1 Pyrex glass measuring cups for liquids. As for measuring dry goods, I could careless. The plastic ones from the dollar store suit me fine.
I recommend a good set of heat resistant spatulas that can take heat to about 450 degrees. If you have a Kitchen Collection near you, they sell a nice set of 4 for $10 or less.
I know they are a lot of money but depending on the kind and quantity of baking you may want to invest in a Kitchenaid stand mixer. There is nothing like them especially on stiff doughs.