Stock PotOf course you can make virtually anything work, but the best soup pots will work with you. On first glance, the $12 version you can get from your local discount store seems fine. It's big enough (often 12 quart or larger) to contain that large batch you want to make but that's only part of the equation. Broth-based soups often need to simmer for a long time, and cream-based soups scorch easily. You'll want a pot that keeps your delicious concoction from burning if you turn away for a bit. In addition to size, look for something that's heavy and has a bottom made of multiple metals bonded together. A common combination is a stainless steel outside with aluminum layers bonded to the bottom. You'll also want a lid that fits well. This version from Williams-Sonoma is a good choice, and this copper pot is the gold standard (but for $600 I would expect someone to actually deliver weekly meals to my house as part of the deal). I use an 8 quart Classic Farberware stockpot that I got for a wedding gift a long, long time ago and it's still in great condition!
My least favorite thing about serving soup is the presentation. After carefully preparing ingredients and tweaking seasonings to perfection, I hate just plopping the possibly less-than-attractive kettle on the table. The alternatives are to keep the kettle out of sight by serving from the kitchen (not always practical when soup is a main dish for a family who will likely want seconds), or use a soup tureen. A tureen is typically porcelain or stoneware and has a lid to keep things warm. You'll want to look for one that's a reasonable size for your needs and, since it involves transporting a gallon of boiling hot liquid, look for one with a very stable base and useful-looking handles. (TIPS AND TRICKS: About 10 minutes before using your tureen, fill it with boiling or very hot water and then pour it out just before filling with soup. The hot water will warm up your dish and that will keep your soup hotter when served.) A tureen will typically come with a matching ladle.
There's one more dish that I bought recently for someone who likes to take soup for lunch. This CorningWare mug has a lid that really fits well and seems to be leak-free. It's big enough for a generous serving and microwaves much better than the plastic bowl he was using. Hardly essential, but I do recommend the product. (I got it at Wal-Mart for less than the price listed on the Corning website.)