A stainless steel set with pots and pans (how big of a set depends on your cooking habits).

I have a tramontina set, tri-ply base and all metal including the handles of the pots/pans and the handle of the lids and it's great quality. I can make anything from soups, stews, risotto, pasta sauce, prawns or fish in them. Things don't stick and they clean easily.

Pick a brand without necessarily following brand names given here. The same brand can have amazing products and crappier ones. Just make sure whatever you get has a thick bottom so things don't stick and there are no plastic handles.

And pyrex food containers. They're borosilicate so they can go in the freezer and the oven as well (without the lid). They're also dishwasher safe.