So my 17 year old box style 54cm TV finally packed up and it seems I need a new one according to my family.

We are not big TV watchers, but we have children... So maybe its time for a LED flatscreen.

What does one have to look out for when buying a TV?

Smart versus normal?
Curved versus flat?
Resolution?
Hertz?
Contract ratio?
Wifi/LAN/internet?
Is a long warranty worth its salt or neglible because they pretty much all last as long as the warranty?
Fancy global brands vs SINOTEC and HISENSE and co?

And what technical specification is important and which not so important?

Any advice/tips welcome.