Ooooo, really depends on what you're going for.
Here's what you should have:
-Instantpot or whatever those things are called. I need one of these.
-Enameled cast iron dutch oven. I have two Le Creusets (wedding gifts). I can't speak to the quality of any brand besides these ones. You can probably buy cheaper ones that still do the job just fine.
-Cast Iron skillets. These are great work horses. By far the best value for your dollar. If you can get older ones at estate or garage sales, do it. Modern Lodge skillets are great for most things.
-A stainless steel saute pan, and I'd aim for 5 qt. Basically for particularly good fond and anything you don't want in your cast iron skillets (like highly acidic reductions, IE pasta sauce or wine reductions). THIS NEEDS A LID. You don't need to USE the lid for everything, but you need it as an option.
-2 stainless steel saucepans of different sizes. I have a 2 qt and 4 qt and they are busted out for different things.
-8 qt stock pot. Or more. It's great for pasta, and for making stock, and for making large batches of soup.
-2 non-stick skillets, cheap as you can get. These are ideal for pancakes and eggs. They are not good for anything else. You can make pancakes and eggs on your cast iron (and I often do), but the clean-up will generally be much messier.
-Casserole dishes are necessary, but I don't have any good advice on those.
-A baking sheet and a rack for roasts. You can go cheap here, too.
If you CHOOSE to splurge (and it's a CHOICE), splurge on your saute pans and saucepans. You will want to get a tri-ply product. Wal-Mart has the tramontina brand. Cuisinart has Multi-Clad pro. Most spendy-pants prefer All-Clad, but you can get SOME All-Clad products at a pretty good sale at least some of the time. Honestly, I am not going to spend $300-350 on a pan if I can get something from Wal-Mart or Cuisinart that does 80% of what I need for, like, 80-90. You can get an 8" Tramontina skillet for $25, and I think the All-Clad equivelant is like $70.
All-Clad is a superior product, no doubt, but definitely spendy-pants.
These products essentially heat up more evenly so you have fewer hot spots on your pan, while still holding heat well (so your sizzling 400 degree pan doesn't drop to a useless 300 when you drop in food), and transferring it well (though not as good as a cast iron, so you still want to sear your steaks on a cast iron).
A few nice extras, but not necessary:
-A Saucier. These are sort of like sauce pans, but they are curved on the side like a wok. They are easier to clean and it is easier to make sauces in them. Less stuff gets caught in the corners and it's easier to stir them.
-A Wok. It's great for stir-fry. You can quickly sear pieces of meat or veggies in the bottom, you can do some limited shallow deep-frying, and there's lots of space for rice and veggies and all sorts of deliciousness. Much like a saucier, it has curved sides which makes for easy stirring and easy clean-up.
-Huge ass covered roasting pan. This gets hauled out when I make a 25 pound turkey.
For smaller spaces, drop the non-stick skillets, drop the larger of the two sauce pans, drop the stock pot (use the dutch oven instead).