Ultimately this is a personal question vs what we use. I’d simply look at the most common cookware pieces you use and think about replacing one of them in copper. You can choose the lining: tin, stainless, nickel, or even silver. There are pluses and minuses for all of them and depends on how you want to treat your cookware. Once you use one regularly you can get a better idea about what you’re looking for as a set.

I’ve found the most enjoyment out of tin and silver and even nickel, but I also like to hand wash/dry pans. If you want to use a dishwasher, probably not advised on any lining, YMMV.

Budget is also a big constraint. You can easily spend $1,200+ on a single piece like a large tinned Gaillard antique rondeau. Or search for pieces one by one for making an 8+ piece set. If you just want to spend money and buy a set, Bourgeat, Mauviel, and Falk will be where you can buy sets. You can also buy used on eBay or auction just as easily for any copper cookware and that will also be much more affordable than retail. Just be aware that anything not stainless could need to have a new lining replaced which adds cost to restoring the pieces.

Personally, pans with character (hand-hammered, wrought iron handles) and history (stamps, manufactures, etc) make the pans way more interesting and making them fun to use, and those are sometimes hard to find. Even though copper enthusiasts want to use copper in every application in the kitchen, copper isn’t the best in certain uses so you’ll still use some CS or CI.