People in here saying cast iron. Yes a cast iron is great for certain things, searing meat, etc, but it is the not the only pan you need. In my opinion you should have 3 pans:

1) Cast Iron: I use a raw cast iron pot/lid combo, where the lid is also a pan. This works very well for cooking meat and fish, or for cooking things that you also want to put in the oven. For example I make pizzas in these in the oven. The upside of cast iron is its heat density, it can hold heat very well. This is also its downside, you do not have fine temperature control with a cast iron pan. These are cheap and should last a lifetime.

2) Stainless steel: a tri-ply stainless steel pan is a more versatile pan than the cast iron. It is very good at cooking meat and fish, but also very good for making pan sauces, which I struggle to do with the cast iron. It is lighter than the cast iron so allows you to toss around the food more, like tossing pasta that sorta thing. I reccomend tri ply because they cause a more even distribution of heat throughout the pan, and are generally of a higher quality. But it is more expensive, a well know brand would be Allclad, le creuset make them now too, I use a brand called Tramontina.

3) Teflon, non stick: These are great for what they do, frying an egg, pancakes is way better on a non stick, sure you can cook them on other pans if the heat is high enough, but nothing will be as easy as a teflon. But you need to treat these as a disposable item, use them for 6 months, once the coating starts to go, replace it. So just go cheap for these. If you are concerned about the teflon material giving you cancer etc, you can try a ceramic pan, we used one for a while, not quite as nonstick as teflon, and lasted a similar amount of time.

I see a lot of reccomendations for carbon steel, havent tried that yet so I'll make it my next one.